When City Radio opened on Cortlandt St. in 1921, radio was a novelty. Over the next few decades, hundreds of stores popped up. The six-square-block area around Cortlandt Street in lower Manhattan was a bazaar of radio tubes, knobs, and antenna kits. Metro Radio, Leotone Radio, Cantor the Cabinet King. For more than four decades it was the largest collection of radio and electronics stores in the world. Then in 1966 the stores were condemned and bulldozed, to make way for the new World Trade Center.
Check out this 1929 film by Fox Movietone of Cortlandt Street: