Vent Stack

[Image: The Holland Tunnel Land Ventilation Building, courtesy of Wikipedia].

As described in this PDF, Holland Tunnel has four ventilation structures:

The four ventilation buildings (two in New Jersey and two in New York) house a total of 84 fans, of which 42 are blower units, and 42 are exhaust units. They are capable, at full speed, of completely changing the tunnel air every 90 seconds.

David Gissen briefly explores the architecture of NYC tunnel vents in his book Subnature, opening a window onto the architecture of subterranean weather generation, where unseen machines suck whole atmospheres from the depths of the city. Perhaps we'll even read someday that New York's ongoing rash of tornadoes includes a few rogue climate systems belched forth from these vent stacks on the autumnal banks of the Hudson (or perhaps not).