Today in History, November 21, 1927:
Time magazine places the recently opened Holland Tunnel between New York City and Jersey City on its cover. On its first day nearly 52,000 vehicles used the tunnel. Running a tunnel beneath the Hudson River, or any river, would have been suicidal before engineer Holland designed a ventilation system that took up four ten story towers, two on each end of the tunnel. Fresh air is pumped through vents at the bottom of the roadway while the air is drawn out simultaneously through vents in the ceiling. All of the air in the tunnel is changed every 90 seconds.