“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‘sdesk, is a committed futurist: “The light is artificial and indirect. Its color and intensity have been determined by a long series of expert tests. It never varies: day and night, summer and winter, rain or shine, it is always the same; unvarying in its brightness and efficiency” (16). He praises a working scenario much like the one Tom Wingfield [the hero of The Glass Menagerie] finds unbearable and which social historian Lewis Mumford would later critique: “With air conditioning and all day fluorescent lighting, the internal spaces in the new American skyscraper are little different from what they would be a hundred feet below the surface. No extravagance in mechanical equipment is too great to produce this uniform internal environment: though the technical ingenuity spent on fabricating sealed in buildings cannot create the equivalent of an organic background for human functions and activities” (480-81).

See also the underground worker cities in Metropolis.