BROOKLYN - Private tours are now being offered at the Brooklyn Army Terminal.

The 95-year-old structure in Sunset Park used to be the largest reinforced concrete building in the world.

Today, many people do not even know it exists. This spurred tour guide Andrew Gustafson’s mission to raise awareness by offering private tours.

On his tours, Gustafson explains how the terminal used to be a major military building until the 1960s. Now, more than 100 businesses are housed there.

Brooklyn Army Terminal currently has more than 3,000 people working on its premises keeping the memory alive. 

For more on the terminal, watch the clip to the left or click News 12 Extra on Optimum TV channel 612.