[WATCH] What's Under Your Feet in New York City?

The video takes viewers on an extensive tour of New York City's complex and often invisible underground infrastructure. It delves into the city's unique systems, including its gravity-fed water network and the extensive underground electrical distribution system, particularly highlighting the reliable "secondary networks" that keep the lights on in densely populated areas. The largest district heating steam network in the world, the challenges of thermal expansion, and the ongoing efforts to manage steam leaks are also explored. Viewers learn about the natural gas pipelines, the telecommunications conduits managed by companies like Empire City Subway, and the complex history of the city's combined sewer system, which still occasionally leads to combined sewer overflows despite ongoing remediation projects like those at the Newton Creek Wastewater Treatment Plant. The intricate layers of subway tunnels, including the massive and deeply buried Water Tunnel No. 3 project, and vehicular tunnels like the Holland Tunnel that connect the boroughs and neighboring states, are also detailed. The video underscores the monumental engineering efforts required to build and maintain this subterranean city, which is an almost incomprehensible "city within a city".