The vortex of water appeared in a harbour off the east coast of Japan after an 8.9 magnitude earthquake struck the country earlier today.
Footage taken from a helicopter shows a boat dangerously close to the centre of the pool. It is not known whether there was anyone onboard. The quake, which hit at 2:46pm local time, triggered a tsunami that washed ashore ships and devastated all in its path.
Waves up to 30 feet high engulfed the coastal city of Sendai, 230 miles north east of Tokyo, and grounded ships in Hachinohe a further 150 miles north.
All Japanese ports have been closed and tsunami warnings have been issued for areas across East Asia and the western coast of South America, the Pacific Tsunami Warning Center said.
The magnitude 8.9 quake surpasses the Great Kanto quake of September 1, 1923, which had a magnitude of 7.9 and killed more than 140,000 people in the Tokyo area. [via The Telegraph (UK), BBC, Live Science and Daily Mail (UK)]