Powered sledges break a trail through Maine's primitive Allagash Forest, on March 5, 1963. Twenty men, led by an expert on Arctic equipment, made an extended trip through the forest to test equipment. Robert Faylor, director of the Arctic Institute of North America, led the group. The sledges, called Polaris vehicles, are powered with engines about the size of an outboard motor and travel up to 8 or 10 miles an hour, depending on snow conditions. (Photo by Dan Grossi/AP Photo)
