American swimmer Lynn Cox Friday became the first person to swim across the cold Siberian waters of Lake Baikal, the world's deepest lake, the official Tass news agency said. Cox, of Los Alamitos, Calif., made the 11.1-mile crossing from Tolsty Cap to Listvyanka settlement in four hours and 20 minutes. The lake was at 51 degrees, Tass said.

The challenge of crossing Lake Baikal was not distance, but coldness, where even in the summer water temperatures can drop below 50 degrees.