On Tuesday, social media users in New York tweeted pictures of the One World Trade Center that appeared to show flames coming out of the building.
The New York Fire Department then responded that the so-called Freedom Tower was not, in fact, on fire.
But the cause of the optical illusion was not immediately clear. Some speculated that it could be the product of water evaporating on the building's powerful lights.
The Port Authority of New York and New Jersey, which manages the building, did not immediately respond to BuzzFeed News' questions about the origin of the illusion.
Nicolás Medina Mora is a reporter for BuzzFeed News and is based in New York.
Contact Nicolás Medina Mora at email@example.com.
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