5. The Tunnel Completely Changes Air Every 90 Seconds

The Brooklyn Battery Tunnel Ventilation Building.

Despite the tunnel’s immense size, it is never in want of clean air. It’s not that hard to imagine an underground tunnel filled with cars being completely saturated with exhaust fumes, but thanks to the design by Ole Singstad, the tunnel is constantly sucking fumes out and bringing in fresh air from the surface. This is all because of the four ventilation chambers in Manhattan, Brooklyn, and Governors Island that are so powerful that they can completely replenish the entire tunnel with fresh air every 90 seconds.