Swimmers dive into a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. According to organisers, about 700 swimmers across China took part in the event on the official launch day of the Harbin Ice and Snow Sculpture Festival. (Photo by Kim Kyung-Hoon/Reuters)

A worker breaks ice on a pool carved into the thick ice covering the Songhua River in the early morning as he prepares the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer dives into a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

Swimmers climb out of a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer reacts after swimming in a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A man swims in a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

Swimmers dive into a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer stands on a platform on a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A female swimmer covers herself with a blanket after swimming in a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer reacts after swimming in a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A worker breaks ice on a pool carved into the thick ice covering the Songhua River in the early morning as he prepares the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province ce January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

Swimmers dive into a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

Frost lines the hair of a spectator as she watches swimmers competing in a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer takes off a gown as he walks to a platform on a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)

A swimmer follows an official from the organiser to his platform on a pool carved into the thick ice covering the Songhua River during the Harbin Ice Swimming Competition in the northern city of Harbin, Heilongjiang province January 5, 2014. (Photo by Kim Kyung-Hoon/Reuters)