A sea monster has temporarily taken over Building 611 at the Navy Yard in Philadelphia.
Huge, inflatable purple tentacles emerge from the windows, arc toward the sky, and are big enough to be seen from the planes flying into Philadelphia.
The tentacles were created by the United Kingdom street art duo Filthy Luker and Pedro Estrellas.
Their art installation was commissioned by an art collective called Group X.
The artwork was unveiled on Monday, which also happens to be National Octopus Day.