French freediver Arthur Guerin-Boeri set a record on Thursday by swimming 120 metres (394 feet) under ice, carried out with one breath in three minutes in a wetsuit but without flippers or gloves.
The impressive feat by the 36-year-old took place in a lake in Finland renowned for having some of the clearest water in the country.
Eight holes spaced 20 metres apart were made in the frozen sheet of ice covering the lake as the daredevil got into the icy water wearing a thick wetsuit and managed to swim a distance of 120 metres in one breath using a guideline.
The five-time world champion spent two hours preparing himself before plunging into the frozen water.
A sauna set up nearby allowed him to warm up before he headed to the starting point where he did breathing exercises for nearly an hour.
He then inflated his lungs "like a balloon," as he told AFP, before getting into the water.
"There is fear, anxiety and it's something I dreaded quite a bit but it was a calculated risk for which I was prepared," he said.
"I manage to lower my stress level and then I let myself get carried by something that transcends me.
"It's all quite mystical but necessary when achieving something like this."
He said during his record three minutes under water he pushed forward using the cable above him as a guide.
"Under the ice I felt pretty good," he said. "There was this diffuse lunar light that was amazing. It's beautiful."
He said he did not suffer much from the cold and planned to try and set another world record in a year, this time wearing a bathing suit.