4. The City College of New York

Rock from the subway tunnels isn’t always used as landfill. According to Kenneth Jackson’s Encyclopedia of New York City, Manhattan schist excavated from the first subway tunnels of Manhattan was used to build the impressive Neo-Gothic structures of the City College of New York, in upper Manhattan, completed in 1907 and designed by George B. Post. Post’s design was one of the first in America to make use of the Collegiate Gothic style. Post contrasted the dark Manhattan schist with white terra cotta trim and adorned the campus buildings with over 600 gargoyles and grotesques.