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 trek across a frozen expanse of Lake Superior, the world's largest freshwater lake, to the sea caves of the Apostle Islands National Lakeshore near Cornucopia, Wisconsin Feb. 15, 2014.
