8. The Holland Tunnel was the longest underwater vehicular tunnel in the world

The Holland Tunnel was not only the first underwater vehicular tunnel in the Hudson River, but it was also the longest in the world when it opened. According to the ASCE Metropolitan section, it also had the largest tube width in the world, at 29.5 feet, setting the standard for other vehicular tunnels throughout the world that followed.

Since the Holland Tunnel was completed in 1927, New York City has welcomed a handful of new tunnels, including the Lincoln Tunnel and the Brooklyn-Battery Tunnel. At 9,117 feet long, the Brooklyn-Battery Tunnel now holds the title for the longest underwater vehicular tunnel in New York City. When the Rogfast Tunnel in Norway is completed, it will be the longest and deepest underwater vehicular tunnel in the world at 17 miles long.