A participant competes in the 5th Tyumen Open Cup winter swimming contest in the Siberian city of Tyumen, Russia December 5, 2019. REUTERS/Alexey Malgavko

A participant competes in the 5th Tyumen Open Cup winter swimming contest in the Siberian city of Tyumen, Russia December 5, 2019. REUTERS/Alexey Malgavko

A participant competes in the 5th Tyumen Open Cup winter swimming contest in the Siberian city of Tyumen, Russia December 5, 2019. REUTERS/Alexey Malgavko

A participant gets out of water after competing in the 5th Tyumen Open Cup winter swimming contest in the Siberian city of Tyumen, Russia December 5, 2019. REUTERS/Alexey Malgavko

Participants pose for a picture inside a barrel with hot water after competing in the 5th Tyumen Open Cup winter swimming contest in the Siberian city of Tyumen, Russia December 5, 2019. REUTERS/Alexey Malgavko