YOUTUBE, Published on Feb 4, 2014
RUSSIA. In the city Novokubansk - Administrative Region of Krasnodar Krai - located on the banks of the Kuban river, a strange phenomenon happened in the frozen waters. A piece of ice - with a weird, strictly circular shape, appeared on the surface, moving itself in rotation on its own axis - without any apparent cause.
Some observers cogitated that the movement could have been caused by the currents of water in liquid state - beneath the ice sheet but the hypothesis wasn't confirmed and not explains the precision of the cutting.