Answer: A steerable docking station
In the original plans of the Empire State Building, the massive mast was designed to act as a docking station for dirigible airships. The investors behind the building of the building insisted that it was a practical investment when in reality it was almost a bid to build the Chrysler building with 204 feet in order to claim the crown as the world's tallest building. 1
9659003] Today's airship captains declared the idea ridiculous and dangerous. The closest that came to actually mooring at the mast was a jury-rigged three-minute connection to the top of the building in winds of 40 kilometers per hour. In addition, there was a drop of a pile of Evening Journal newspapers via a 100 foot rope and some simple flybys for publicity photos. The most popular photo on the subject (and what is seen here) is a composite created to promote the idea of an aircraft docking with the building. At the end of the year, the mast was transferred to NBC to act as a television broadcasting tower.
Image, a 1930 composite, courtesy of Keith de Lellis Gallery's 2010 Birds Eye View Collection.