Adventurer Jon Turk on his latest expedition, 1,500-mile circumnavigation of Ellesmere Island by kayak

Buck spoke May 11 with Jon Turk, environmental scientist and adventurer, about what drives him to undertake extreme adventure, what it takes to succeed, and pushing one's body to these limits at age 66. Jon recently completed a 1,500-mile circumnavigation of Ellesmere Island by kayak with his expedition partner Erik Boomer; it's believed to be the first ever.