GREENBURGH, Westchester County -- The Baikal Ice Marathon is a standard length marathon: 26 miles long.
But there is nothing standard about where those miles are run: across the frozen surface of the deepest lake in the world, Russia's Lake Baikal in southeast Siberia.
The marathon takes runners across from the lake's eastern shore to its western. In March, when the marathon takes place, the ice is a meter thick and stretches iron-hard and flat across waters that in places are a mile deep.
Early spring temperatures on the lake are locally considered mild -- around 14 degrees Fahrenheit. But they can -- as they did this year -- drop to minus 20 Fahrenheit. Gale-force winds can blast across the lake, whipping up huge spiraling clouds of ice that burn the face and eyes. In such winds, frostbite can occur within half an hour.
Each year, 150 people sign up for this test, traveling from around the world. They stay in two small towns near the lake. The ice is thick enough to support cars but participants travel to the starting line by hovercraft.
Among those running is Alicja Barahona, a 64-year-old resident of Greenburgh, Westchester, just outside Manhattan, and about 6,000 miles from Baikal. For the past 20 years, Barahona has been running ultramarathons - extreme long-distance runs usually over hundreds of miles and often in exceptionally harsh environments, such as deserts and mountain ranges.
Watch the her story below and read more about Barahona on abcnews.com.