A very unusual and impressive sight took shape in Maine this week, a nearly perfect disc of ice — forming in the Presumpscot River.

The massive ice disc drew curious onlookers to the banks of the river. It’s not clear how or exactly when it formed.

According to an official with the city of Westbrook, the disc is roughly 100 yards across and is spinning in a counter clockwise direction.

That same official captured this breathtaking drone footage of the amazing sight.