People have been left baffled on social media

The creepy-looking building has caught people's eyes due to it's windowless appearances with plenty of wild theories about what goes on behind the doors being speculated.

From an office full of vampires to the Men in Black headquarters, it's mysterious look has got many talking.

Images of the building have been around before, with Tom Hanks even tweeting back in 2017: "This is the scariest building I've ever seen! WTF goes on inside??"

In recent days the image has resurfaced again Twitter and Reddit, leading to even more speculation about what could be inside.

One user said: "Lizard people don't need windows," while another wrote: "Gives off MI-6 vibes."

Sadly for everyone, all of the wild rumours about aliens and vampires isn't true however there are reportedly some dark tales behind it.

Located on 33 Thomas Street in New York City, the skyscraper is also known as the Long Lines Building.

Designed and built between 1969 and 1974, it house one of the most important telecommunications companies in the USA - AT&T (the American Telephone and Telegraph Company) before they left in 1999.

According to an investigation carried out by The Intercept in 2016, there's more secrets behind the walls of the building, with their findings leading them to believe it's a secret base of the NSA (National Security Agency). 

Documents leaked by Edward Snowdon gave "compelling evidence" to suggest it was used by the NSA surveillance site, code-named TITANPOINTE.

When asked, the NSA declined to comment and the mystery behind the building still rumbles on to this day.