The Spectacular Ice Caves of Lake Superior
For the first time in five years, visitors can walk, ski, or snowshoe more than a mile on frozen Lake Superior to check out ice caves formed by crashing waves at the Apostle Islands National Lakeshore in Wisconsin
Eric Miller / Reuters
Sightseers crouch to avoid icicles in a sea cave on frozen Lake Superior, the world's largest freshwater lake, at the Apostle Islands National Lakeshore near Cornucopia, Wisconsin Feb. 14, 2014.