9. 20 Exchange Once Had an Observation Deck (Probably) 

According to the book Skycraper Rivals by Daniel Abramson and Carol Willis of the Skyscraper Museum, the building’s plans featured an observation deck on the 57th floor. If it did, it was closed not too long after. The building isn’t listed as having a deck in 1939’s “WPA guide,” unlike neighboring 40 Wall Street, 70 Pine Street, and the Woolworth Building.

There’s nothing to suggest that there was ever an observation deck on the roof. Despite the nice arches, the roof is filled mostly with massive equipment that isn’t going anywhere anytime soon.