to learn more about this beautifustcte,e t th arittul storian justin ferate. justin is internationally coized for his expertise in new york city landmarks. why was this bridge originally built? >> in the 19th century, the city ofeworwathlaesin the country. and the third largest city was the city of brooklyn, directly across the water. but there was no way to connect e o ti. the east river was a tremendous shpi cal so ty had to fure a way to get from one side to the other and connect the citiend g over all the ships that came into the harbor. >> no one had ever attempted to build a bridge like this before. r e in t terth support the bridge would have to go deep beneath the sandy river bottom to make sure they rested on sidurface. but that meant building underwater. so- >> they created aather amazing, simple, but amazing simple een box upsidedown, and they would sink the box andapreirn e box. d op wldo wnnt the box, digging for the foundations for the bridge. basically, you're in an upside wnoxunrnth the river. an incredibly difficult job, but it was the courage