Russian ice divers put up New Year's tree in frozen Lake Baikal Nothing seems impossible for a trio of Russian ice swimming enthusiasts who put up an artificial fir tree on the bottom of the world's deepest lake to celebrate the country's holiday. The tree was installed near the shore, at the depth of some 3 meters, after the swimmers cut a hole in the thick ice. They said the water temperature of just above 0 degrees Celsius and an icy wind did not deter them.