A giant ice wall extending more than a dozen kilometers has risen on Xingkai Lake, a border lake between China and Russia.
Standing around 20 meters high, the wall in northeast China's Heilongjiang Province is made of chunks of ice, piled up by strong winds.
"It was only three to four meters high at the beginning. But now it is 20 meters high," said Sun Yunge, an official with publicity department of Mishan City.
Xu Zhong, head of the meteorological station at Xingkai Lake, said the phenomenon is rarely seen as it needs lasting low temperatures, strong winds, water flow under the lake surface and ice chunks to form.
Visitors are calling it the Great Ice Wall.
"It was amazing. I've taken a lot of photos here," said Wang Xiaoli, a 32-year-old visitor from Harbin, Heilongjiang's capital.
As the largest freshwater lake in northeast China, Xingkai Lake is well-known for its abundant biodiversity and complex ecosystem. It is a major habitat for migratory birds in the Asia-Pacific region.