Where are the windows?
It's located at 33 Thomas Street in New York City and is also known as the Long Lines Building.
It was designed and built between 1969 and 1974 to house AT&T (the American Telephone and Telegraph Company) telephone switching equipment - one of the most important telecommunications hubs in the USA.
The equipment required a high level of space and a secure location, therefore the building's floors are taller than average.
Despite being as high as a 40-story tower, it actually only has 29 floors.
The skyscraper is also rumored to be originally designed to withstand a nuclear blast and had enough food to keep 1,500 people alive for two weeks in the event of a catastrophe.
People on social media are left baffled by a mysterious skyscraper that's as tall as 40-storeys in New York City. Theories range from an office for vampires to Men in Black headquarters.
www.dailymail.co.uk