Cross-country skiing in the National Wildlife Refuge System

Get your heart pumping, your muscles stretched and your lungs refreshed with some cross-country skiing at dozens of refuges, including Kootenai National Wildlife Refuge (top) in Idaho, Great Swamp National Wildlife Refuge (bottom left) in New Jersey, Aroostook National Wildlife Refuge (middle) in Maine and Tamarac National Wildlife Refuge (right) in Minnesota.