A massive rotating ice disc has formed in a river in the US state of Maine.
The circle of ice is 91 metres wide and appears to have formed perfectly naturally.
The disc in the Presumpscot River has been compared to an alien spacecraft, and has also served as a giant raft for ducks and other birds.
Footage of the formation gently spinning in the water has gone viral, with people around the world seemingly mesmerised.
Take a look for yourself in the video above.