Oussama Mellouli of Tunisia won the gold medal in the men's swimming marathon at the Olympics in Londoni on Friday, to become the first swimmer to get medals in the pool and open water.
Mellouli, 28, previously won the 1500 metres freestyle gold at the 2008 Beijing Olympics
Thomas Lurz of Germany won the silver medal and Richard Weinberger of Canada the bronze.
Mellouli took the lead on the fifth of the six loops in the 10km race in the Serpentine in Hyde Park and no-one else could keep up with him.
"I can't explain it, I can't really describe it," he said afterwards.
"I've been struggling, with my shoulder, my elbow, I had a virus.
''What happened today is a miracle if you believe in miracles," Mellouli said.
A huge crowd lined the banks to watch the race, which was introduced into the Olympic programme in Beijing four years ago. The lake was constructed in 1730.
A national hero in his homeland, Mellouli became his country's first double gold medallist.
He also won the world championship for 800 metres in 2007 but was stripped of his title and banned from competing for 18 months after testing positive for amphetamines at a meeting in the United States in late 2006.