The expanse became home to about 1,600 people — many of whom were escaping the crowded and increasingly dangerous conditions of lower Manhattan. Among them was a predominantly black community that bought up affordable plots to build homes, churches, and a school. The area became known as Seneca Village.

The "forgotten city" refers to the layers of abandoned transit and retail infrastructure hidden beneath NYC. The most famous is the Gimbels Passage, a 360-foot pedestrian tunnel built in 1910 that once connected Penn Station directly to the Gimbels department store basement. In 2026, it remains sealed due to its dark history of crime in the 1980s. Another major "ghost" site is the City Hall Subway Station, a masterpiece of Guastavino tiling and chandeliers that was closed in 1945 because its curved platform couldn't accommodate newer, longer trains. Additionally, there are the "under-Penn" tracks and the remnants of the Atlantic Avenue Tunnel (the world's oldest subway tunnel). These spaces represent a subterranean Gilded Age that still exists, largely untouched, beneath the feet of millions of commuters.