The Greatest Projects Never Built; Extreme Engineering; Scientific American Presents; by Alpert; 4 Page(s)

To the ancient Babylonians, it must have sounded like a wonderful idea. "Let us build us a city and a tower, whose top may reach unto heaven; and let us make us a name, lest we be scattered abroad upon the face of the whole earth." At least that's how the Book of Genesis tells the story. The construction started well: the builders had plenty of brick, mortar and laborers. What they didn't count on was the wrath of the Lord. Outraged by the ambitions of the early engineers, the Almighty killed the project by forcing the workers to speak in different languages. The Tower of Babel became the first in a long line of marvelous structures that, for one reason or another, were never built.

In the past century alone, visionary architects and engineers have proposed a host of stupendously impractical projects. Some prominent examples are the milehigh skyscraper, the nuclear-powered airplane, the Superconducting Super Collider and the L5 space station. Divine anger didn't kill any of these plans-they were done in by extravagant costs, unforeseen construction problems, shifts in political backing and the often belated realization, "Hey, do we really need this thing?" The history of these proposals suggests a basic lesson that should be taught in all engineering and architecture schools: just because something can be built does not necessarily mean that it will or should be built.