Adventurers paddle their canoe to an extraordinary ice tunnel on top of a glacier. To get to the beautifully blue, hidden 'supraglacial lake' the group had to climb 50ft walls of ice.

It took hours for the group of 'glacier tourist guides' Brett Winterbottom, 27, Warren Maddox, 26, and Shannon Kaelin, 24, to get to the lake in Alaska. Photographer David Crane, who took pictures of the daring trio, revealed it was the first time they had managed to get a boat to the top of...
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