Russian winter swimmers, also known as "walruses", took to the freezing waters of Lake Baikal to mark national Walrus Day.
The athletes plunged into the 4-Celsius-degree (39 Fahrenheit) water of the lake, which rarely reaches more than 10 Celsius degrees (50 Fahrenheit), even in summer.
Sergey Kushnaryov, a winter swimmer, said that it is "better to swim all year round" rather than to wait for the warmer season.
Many "walruses" believe that winter swimming helps them to resist colds and improves their overall health.
Ice water swimming, or "walrusing", is a common activity in colder countries, including Russia.