Before there was Michael Phelps or Ryan Lochte, there was Lynne Cox. And while she’s never competed for Olympic gold, she did break down barriers when she swam across the Bering Straight, from the island of Little Diomede in Alaska to Big Diomede, then part of the Soviet Union.

Her 2.7-mile swim — which took place in 40 degree waters — crossed what was known as the "Ice Curtain," the border between the United States and the USSR. Both Ronald Reagan and Mikhail Gorbachev praised her success, and the world applauded her accomplishment. This weekend marks the 25th anniversary of that swim.

"I trained in very, very cold water for many years," Cox says. "That Bering Strait swim took 30 years of preparation." Beyond the Cold War implications, the swim also provided information on how much cold human beings can stand, and opened the door to extended research in that field.  

At the end of the day, though, it was just another tough swim for Cox. "One stroke in front of the other," she says. "You think about it, dream about it, prepare for it." It took 11 years just to secure approval from the Soviets before then-General Secretary Mikhail Gorbachev granted her permission.  

"You feel this huge surge of cold rushing through your body," Cox recalls. "It was really, really hard." 

At the age of 15, Cox broke the record when she swam the English Channel. Since then, she has successfully navigated New Zealand's Cook Strait, the Strait of Magellan, and even the Cape of Good Hope. Researchers have attributed her ability to swim in cold temperatures in part to perfectly distributed body fat, which acts as a natural insulator. 

"Last summer it took one brave American by the name of Lynne Cox just two hours to swim from one of our countries to the other," Gorbachev said soon after the swim. "We saw on television how sincere and friendly the meeting was between our people and the Americans when she stepped onto the Soviet shore. She proved by her courage how close to each other our peoples live."