“The cost to burrow down is dropping, while the price (and hassle) of erecting a skyscraper in a dense urban area just keeps rising. The breakthrough comes thanks to tunneling technologies that are now being used on huge transportation projects, like Boston’s Big Dig and Moscow’s Lefortovo highway tunnel project. Over the next 10 years these techniques will be used to hollow out space beneath the world’s great cities.” –Sub-Urban Renewal: Thanks to new tunneling technologies, real estate trends are down. Way down.Wired)
The City in History: Its Origins, Its Transformations, and Its Prospects. New York: Harcourt, 1961.]
[Elmer Rice's 1926 play The Subway prefigures some of these observations. Here's a passage from Technology in American Drama:
[The Subway] opens in a windowless office at the Subway Construction Company, which builds tunnels far below the ground and skyscrapers high above it…. The office manager, Bradley, who disapproves of the rose on Sophie
See also the underground worker cities in Metropolis.