The cities of the world are great engineering feats. From the earliest habitats of man constructed out of the raw materials of his environment man has used his ingenuity to work engineering wonders that improve the circumstances of his existence. Since most of the ancient cities we have come to know had already reached a high state of development, it is difficult to realize the long transition of engineering from early, simple hunting camps, hamlets, and villages to the spectacularly engineered urban centers that are Peking, Paris, Rome, or New York. Yet this transition did occur over time, and its earliest manifestations must have expressed themselves in much the same form as elementary human habitations existing in many parts of the world today. The important fact is that man, through his engineering technological skills, has steadily altered the environment and his habitat to suit whatever activity was currently thought to be important.

The most ancient cities of which we have records contained colossal engineering works. At Babylon were constructed two of the wonders of the ancient world; they would be wonders in any age. They were the hanging gardens and the walls of the city's main line of fortification. The hanging gardens were built in terraces so large that residences with full-grown trees could be accommodated with the other garden plantings. The city walls were of double construction—an outer wall, 10 feet thick and 55 feet high, and an inner wall, 25 feet thick and 55 feet high. A 50-foot space separated the two walls.

Long after Babylon faded into history and became "interesting mounds" in that region between the Tigris and Euphrates, the bricks of the city were "mined" and reused to build many other cities of the area.

The Babylonians did not restrict their engineering skills to buildings and fortifications. They developed extensive canals and irrigation systems that transformed the desert into a garden and controlled the distribution of water for agriculture and transportation.

It was not mere happenstance that such a civilization occurred. The ingredients for a giant step were at hand, and in such a mix that it required control of only one factor—the river waters—to produce an environment tremendously favorable to man. Control of water in the fertile crescent, an engineering feat of no small magnitude, transformed the area from one hostile to man to one that produced food surpluses and, consequently, the knowledge and leisure time necessary to produce a great city.

The pyramids of Egypt, although they are not parts of cities and do not perform any function normally considered part of city life, nevertheless represent an engineering tour de force by people already settled into cities. The building of the pyramids recently has been hypothesized as the first public works project. It provided the potential for year round employment and commonness of purpose, thus laying the groundwork for the establishment of the first true nation. Although their direct utilitarian purpose now is obscured, the scope of the engineering involved is indicative of the intellectual and technological skill of the people. In Egypt too, man had mastered the techniques of irrigation and reaped the benefits of an engineered environment in which food was plentiful and citizens were freed to develop civilized arts and crafts.

Other engineering feats illustrate the technical prowess of early city builders; the Great Wall of China and the pyramid building of Central America are two examples. One of the high points in engineering was the iron-making technology of the Etruscans who settled parts of the Italian peninsula before the Romans. They developed arts and crafts to a high degree, including schools of higher learning, and they also mastered the arts of agricultural engineering and successfully applied swamp drainage and irrigation systems to create productive agriculture. If the artwork of the funerary remains is an indication, the Etruscans were a happy and contented people.

The size of their iron industry for that day is overwhelming. The Italian government has "mined" the large mounds of iron ore found in the vicinity of some of the ancient Etruscan ironworks and produced from these mounds which were a sizeable proportion of the steel used by Italy in World War II which were the slag heaps from the ancient Etruscan smelters.

Little is known of the effects of these developments on the health and well-being of those who labored to accomplish them, but it is probable that these technological advances were achieved at great cost to their health and well-being. However it is unlikely that the labor on such a great engineering project as the hanging gardens of Babylon affected the life expectancy of the laborers compared to the non-laborers of that day. The same water-borne diseases that plague those areas today did so when the canals and irrigation ditches of the Babylonian or Egyptian countryside were built, and must have taken a substantial toll then, as now. Only recently have schistosomiasis and malaria been understood well enough to be coped with, and even modern medicine leaves us with a difficult struggle.

So the building of the early cities exacted their price—not only because the work was difficult, but also because cities concentrated people and increased the threat of contagious disease. Nevertheless, the advantages outweighed the disadvantages, and the growth of cities progressed steadily for 20,000 years.

Started as experiments to exploit the advantages of selected environments, cities soon became the hubs of industry and wealth production where information could be exchanged easily and surplus wealth was available to convert information and ideas into the 3-dimensional reality of the engineered world. This reality was not man-centered; it was wealth- and power-centered.

The first cities proved conducive to the enhancement of man's technological abilities, and offered an additional bonus, livability. This quality of livability was a "side effect" of their having been built to accommodate man—the principal instrument of labor. Recent studies of ancient Greek cities demonstrate this point. The spatial relations of these cities were such that all the parts were readily accessible on foot by all inhabitants and walking was the principal means of locomotion. The living conditions might consist of squalor; the work might indeed be life shortening; but the spatial arrangement, similar to stables that accommodate draft animals, had the built-in relationships of a human ecological community. As machine labor supplanted human labor, cities would be built to accommodate the industrial machines of man in preference to man himself—proving that cities design themselves around the work "force." Still later, cities would be built to accommodate the automobile. But the early cities had only to accommodate man—the draft animal. The concept may have been crude and passive, but it was effective environmental engineering. At a higher level of both awareness and humanity we are turning to this concept again, but now it is called "passive design."

The living quarters of such ancient cities as Catalhuyuk, on the Anatolian Plain of Turkey, seem to have incorporated elements of defense as well as comfortable living, and it is not surprising to find comparable dwellings in the modern world. The houses were entered not by doors in the vertical walls but by holes through the roof, access to which was gained by ladders. That the culture was high even for the 13th century B.C., is evidenced by the complexity of stonework, which included decorative items. The masonry and construction also were quite advanced. There is no doubt that Catalhuyuk was a city in every sense of the word and its structure and function are understandable, even if all the individual tools are not.

The Aztec capital city, perhaps more than any other of its day, illustrates the city as marketplace. When Cortez first viewed the central marketplace of Tenochtitlan, he was amazed at its size, extent, and complexity. He was awed by the numbers of merchants doing business and by the orderliness of the process. Vendors with similar products were grouped in common lanes of the market, as were offerers of services, such as barbers. The proximity of so much commercial activity in such a compact, ordered structure points up the physical attributes of information exchange and its effects on the business life of the community.. Perhaps at no place in Europe could such a market have been found at that time. While this Tenochtitlan accomplishment may not rank as an engineering feat comparable to the pyramids of Egypt or the wall of Babylon, it illustrates genius in terms of human engineering and human ecology. The New York Stock Exchange is no more advanced an idea.

The evolution of cities seems to have involved technological devices that took advantage of local raw materials and market centers that utilized the proximity of buyers and sellers to build a rudimentary information system of commerce. Many cities were planned and built to serve special functions, such as manufacturing and industrial centers, administrative seats of government, entrepot centers for the transportation of goods, etc. In most cases, as long as the technology was human-scaled, the cities well and conveniently served the people who lived in them. They probably incorporated living food sources in the form of animals and may even have included agricultural plants within or nearby. As technology increased in scope, the cities shifted from cottage-based industry to cities "zoned" for industry; the cities developed within walking distance of the industry.

One can wonder how the towns and cities of the industrial revolution might have developed if electricity had been discovered before the steam engine. Did construction of the single huge, centralized steam power source cause the stratification of industrial functions, in effect supplanting cottage industry and causing the industrial "zoning?" Would electricity have kept industry human-sized and dispersed? Not only did spatial separation begin with the advent of heavy industry but social stratification was accentuated as well.

A modern city incorporates all the evolutionary stages of city development. So little is known (or applied) about the human ecology of the city that few improvements in cities have occurred in any way other than by happenstance. The proximity factors that seem so important as an ameliorating ambiance in city life did not develop as a convenience to city inhabitants, but to satisfy conditions of business, commerce, or industry. The fact that many of these areas of cities make good neighborhoods after-the-fact is an accident of history. We turn around and see how the system "self-designs" and then set these historic results up as future goals.

The advances in transportation engineering are the main force behind suburban explosion in the United States. First came train transportation from which arose the suburbs of New York. Since the places the train served were established communities, local transportation at first worked to maintain towns and villages. But when the automobile with its door-to-door service became the principal means of commuting, the phenomenon of suburban sprawl was off and running.

Actually, a number of engineering events occurred simultaneously. First, the atomic bomb was invented and used; at the end of World War II there was a drastic shortage of housing; the automobile manufacturers, plugging into increased capacity and demand created by the war, geared up to produce all the cars the nation could conceivably use; and, finally, the proliferation of cars was coincidentally coupled to the construction of the National Defense Highway system. The result changed the face of the nation. Every city of 100,000 was to be connected by interstate highways, and each city was also to have a beltway built to interstate standards. Such a system was to provide needed transportation corridors for the evacuation of cities in the event of nuclear war or its threat, and for years, as the interstate system was being built, the blue evacuation signs pointed the way out of all the cities of the nation. At the same time, the black and yellow fallout shelter signs appeared everywhere, and the nation as a whole was exhorted to build personal "civilian defense" shelters.

The nation failed to respond to the call to build shelters, but it did respond to the new highway system.

Technological developments in the housing industry produced mass housing and U.S. Levittowns sprang up like mushrooms on cheap land made accessible by the mycelium of the growing highway system. In many cities the first beltway was followed by the "outer" beltway, and flight from the inner cities proceeded at breakneck pace. Unforeseen in the original design of the highway system was its rapid saturation by automobiles. The Long Island Expressway was soon dubbed "the longest parking lot in the world," and the highway system designed to evacuate a bomb-threatened populace instead produced a colossal accident toll that someday may approach the fatality score it was originally designed to avert.

The Pennsylvania Turnpike was our first superhighway, and it is hard to believe that it had no separation of opposing roadways and an unlimited speed. Accidents involving 50 or 60 cars became commonplace and hours-long traffic delays because of accidents were ordinary driving experiences. It is estimated that on the Los Angeles freeway system, for every minute traffic is delayed by an accident, ten minutes are required to restore traffic to normal flow.

Workers commuting in and out of Washington, D.C., also are in a paradoxical situation and regularly exceed the posted speed limits. If they drive slower because of rain, snow, or other hazardous conditions and the traffic moves at or below the speed limit, great buildups occur throughout the system. The occasional driver who is ticketed for speeding during the rush hour presents the paradox of the hapless culprit at the side of the road, with the police-car lights flashing and officer in full view, while traffic whizzes past them at speeds over the limit.

The drive-in movie, the drive-in bank, the supermarket with its acres of parking, the drive-in restaurant—each in its own way contributes to the engineering of the automobile society, with its houses on quarter-acre lots spread over thousands of acres of farmland, sidewalkless streets, and school buses. This situation has produced a stratified economy, not only socially but economically.

Because suburban living requires greater instead of less income, inequities in the supply of services occur, straining the budgets not only of the suburbs but of the central cities as well. Central cities, with their utilities essentially paid for until entropy exacts its maintenance toll, were abandoned to low-income families. High-income families live in a suburb, work in a city, require services from both city and suburb, but pay taxes only to one.

The increased interest in the science of ecology and the curtailment of our most common energy sources are combining to produce some interesting alternatives for a society in which energy was thought to be limitless and in which personal transportation was considered a necessity.

The use of the personal automobile made it possible to build diffuse human settlements. Single family, detached dwellings predominate, and shopping centers cluster around huge parking lots with services convenient to drivers. The land used for such schemes was farmland near the city made accessible by the new road systems and economically attractive because of the price differential between farm acreage and suburban building lots. Land suitable for development became so valuable from the tax standpoint that it was impossible to keep it in agriculture. The large amount of money involved overcame most resistance, and high taxes did the rest.

Providing services to such communities was expensive; utilities and sewerage disposals had to be extended great distances to accommodate thinly spread, individual residences. The objective of suburban living was "space" to contrast with city living, and "green spaces" to contrast with the grey drabness of central cities. Suburbs were places to park cars and where green lawns, trees, shrubs, gardens, and other amenities associated with "country" living were found.

The zoning laws usually were such that houses of restricted size and value were built on certain tracts, shoving the suburbs further toward economic stratification. Restricted price classes also restricted the size of houses, and attracted for the most part couples with young children.

Since the youngsters were bused to schools and the parents drove to work, to the grocery, and to other required goods and services, nondrivers who lived in such communities were trapped. The cost of public transportation for people scattered in such diffuse settings was prohibitive, and using public transportation was a sign of lower status in a community where the number of cars indicated family status. Two cars became a necessity for most families, and three or four became commonplace as the children reached driving age.

The engineering considerations of suburban living had to take account of the paradox of providing goods and services on a mass scale to a diffusely settled population. The costs incurred were high, but the income status of persons resorting to suburban living provided the necessary economic basis for such development. The central cities languished as more and more farmland was dedicated to suburban living. In many areas the flight to the suburbs was so rapid that capacity of existing utilities, particularly sewerage, soon was exceeded; the provision of services became the factor limiting the growth of suburbs.

From an engineering standpoint, the design and construction of the suburbs was shaped primarily by the automobile; without it the modern suburb makes little sense. Human values were sacrificed for the convenience of personalized transportation. Ecologically, the suburbs became single factor ecosystems, with enormous dependence on the single factor—the automobile.

Transportation corridors into and out of most cities are clogged with heavy traffic twice a day and are essentially empty at other hours. In the Washington, D.C., area, an entire bridge crossing the Potomac River is restricted to 4-passenger carpools and buses. Roads designed for high speed, low volume traffic are clogged with low speed, high volume traffic. Mere reduction in the number of lanes results in buildups, and stopping at toll booths backs up rush hour traffic into 12-mile long, inching lanes at the Mid-town Tunnel in New York. An accident during the rush hour brings traffic to a complete halt.

At the opposite end of the density scale from the suburbs stands the highrise apartment.

The skyscraper is an American invention. In Chicago, a group of skyscrapers that together represent the historical development of this architectural engineering form has been designated a National Historic Site. The skyscraper and its smaller cousin, the highrise, provide great economy in the use of land for construction. All these forms are related to apartment dwellings, an ancient architectural form. It appeared in the medieval city, in the cliff dwellings of southwest United States, and all through the Indian architecture of Central and South America. The single large building that housed many people or functions is an old invention, but the very large building, the megastructure, is a recently developed, related concept.

The skyscraper and highrise arose as a single-purpose concept, in contrast to the clustering in medieval cities. They were either office buildings or dwellings, never both. In modern cities the construction of skyscrapers and highrises has resulted in severe stratification of population. The Wall Street area of Manhattan illustrates this in the extreme. The area is densely used during working hours but virtually deserted at night. Since there are distinctly different tax benefits relating to business and to residence occupancies, and since the benefits are mostly tilted toward business (in the form of deductions from income tax for the cost of doing business), the stratification tends in the direction of highly segregated business construction.

The concept of "the megastructure" is comparatively new, welding the ancient multifunctional city concept with the modern skyscraper technology and combining all the functions necessary for city operation into one structure. The megastructure would include manufacturing and industry, business and commerce, educational and recreational facilities. Contained within it would be all the services and goods necessary to operate a city, including human residences. The principal means of transportation would be walking, aided by escalators and elevators.

The concept of the megastructure presents in compact form the engineering problems of building for the functional needs of the city—its industry and commerce—and at the same time engineering the environment of its inhabitants.

The term "bio-engineering—is presently used to describe the medical application of engineering to severe human problems of prosthesis. The artificial limbs and eyeglasses of yesterday have been extended to highly sophisticated engineering devices and systems that aid not only in the mechanical, but the biochemical, metabolic, and physiologic problem areas as well. Heart pacemakers are commonplace; powered with long-lived batteries, they regulate the heartbeat of individuals whose biological pacemaker can no longer handle the job. Kidney machines to dialyze body fluids can replace normal kidney function. The devices and machinery to perform human biological functions continue to grow.

But the concept of engineering to provide an essential biological function need not be limited to the functions of an individual. The same concept can be put to use in the larger human environment. To address the structure of a city as though it were a human ecological structure would allow for analysis and solution of many pressing city problems.

The city is a biological community and behaves like one. It is natural therefore to assume that if the biological properties of the city were recognized, proper engineering considerations could be given to solving the biological problems they raise. In short, the city would be ecologically engineered if in fact it were recognized and reorganized as a biological community.

The construction of large-domed stadia to produce uniform climatic conditions for mass-mediated spectator sports has realized the old science fiction concept of the contained city, independent of the climate of the planet's surface. While restricted energy budgets may be spelling the end of wasteful single-use structures of this kind, the need for energy efficiency may very well provide the impetus to turn this level of engineering into more humanly efficient paths.

The Astrodome and the Superdome are not cities by any stretch of the imagination, but they do accommodate 80 to 100 thousand people and fill a great variety of their needs for periods up to 4 or 5 hours per day. The extension of the climate-controlled city concept is not far beyond that of the Superdome, and it relates directly to the megastructure idea.

One way to consider the megastructure is as a "packing" phenomenon packing a city of 250,000 into a cube 5,280 feet on each side. Start by taking all the elements of the city; normal consideration would tell us we are dealing with a myriad of independent structures. But are we really? The buildings of a city are all connected to the same power grid; they are all connected to the same water and sewer system; and they easily may be connected to a common fuel system. The city has a common two-way communication system in the telephone and one-way communication is tuned to a common radio/TV system.

The city is like a giant patch of mushrooms—seemingly independent entities but connected by a pervasive mycelium of communication and service networks. In addition, the city is completely interconnected by transportation corridors—streets, railways, canals, bus routes, auto routes, truck routes, and subways and metros. Each house and building of the city is plugged into the communications, water system, waste disposal, transportation, and power grids. In many respects the modern city is a model of a megastructure, in which only two of a very plausible three dimensions predominate.

The transition between the present-day city and the megastructure is primarily one of spacing—proximity, or packaging concepts that would alter ecological distances and spatial relations and enhance ecological stability.

All engineering of the city has implicitly expressed human ecological relationships, but only because these relationships are inescapable. The fact is that human ecological relationships were poorly understood until recently and most of the great cities of the world are quite old. Building cities primarily to provide opportunities for business, commerce, and industry has been the guiding principle since the very beginning of cities, so it is not surprising that people have been accommodated in the city largely as an afterthought. That is to say, the requirements of man—the biological/ecological animal—were provided only after all other reasons for building the city were satisfied. The suburbs too were designed to satisfy only a portion of the spectrum of human requirements and even these only for the middle span of years. Suburbs suit the home buyers, not necessarily their children or their parents.

The ecological requirements for properly engineering the human community should be just as susceptible to understanding and execution as are the biological requirements which we now satisfy by means of bioengineering for the individual person. The community of human beings can be enhanced by engineering technology in the same way that an individual's functioning can be improved by an electronic limb, a pacemaker, or a kidney machine. What is required is an understanding of the ecological principles and relations governing human communities and the will to engineer these characteristics into the human system. We know what some of them are because we have accidentally built them into our cities.

Recent engineering efforts find us groping toward some of the concepts which are embodied in Habitat, EXPO 67's hit, and engineered amusement centers such as Disneyland and Disney World. We have learned that large numbers of people can be moved, fed, and amused in relatively small spaces, what we still lack is a systematic approach to the human ecology in general and particularly the ecology of human habitation. The city has yet to be recognized as a human ecosystem, and so we still lack the advantages such an insight could bring.

The business, commerce, and industry interests that are the principal factors controlling the structure of the urban ecosystem tend to be a vast collection of single-factored entities, the major effort being to maximize economic gain. Taken as a collection of activities, these functions interrelate and complement each other and provide the real basis for the formation of the city. But when viewed as individual processes it can be seen that, although many of the processes are ecologically related, they continue to operate independently because they are not perceived as an ecological system. Hence, great waste and duplication occur.

Activities which should be functionally and spatially related remain separated and segregated, with human ecology being ignored to accommodate technological and economic conditions. Combined office and living buildings are rare, for instance, because the tax factors for each are so remarkably different. Industrial parks segregate workers from their living areas; large office structures rely upon minimum design standards to provide essentially single function spaces; various sized offices and office suites are formed by rearranging the movable interior wall panels. The replication of only a few simple utilities makes it possible to provide suitable space for a wide variety of office work—because an office requires only a relatively few utilities to accommodate all office functions. Total living would require a great many more utilities and other features, and that would complicate the design of the building. It is by no means impossible to engineer living-working functions into the same building, but the present economic climate simply makes it unprofitable to do so.

But suppose that the same building included living quarters and services as well as working space. Heating and/or air conditioning for the work spaces could be switched to "off" when the spaces were not in use, but the encased nature of the space (interspersed with living and services spaces) would tend to keep the work space temperatures at or near workable levels—obviating the necessity of heating and cooling over long periods of non-use such as weekends and holidays, or else spending extra energy to bring such spaces back to working condition temperatures after shut-downs.