A short hike on Lake Superior leads to spectacular ice caves in Wisconsin.

by Maria Fontoura

In late winter, the waters that lap the northwestern coast of Wisconsin can freeze solidly enough to form an ice bridge to a little-known natural wonder: the sea caves of Lake Superior’s Mawikwe Bay. Formed by centuries of waves cutting into the sandstone cliffs of the Apostle Islands National Lakeshore, the caves are open to kayakers in the summer. But in winter, their red-rock walls are crusted with iced-over waterfalls and clusters of icicles. Accessible for only a few weeks in February and March (call the National Park Service “ice hotline,” 715-779-3398, to find out when), the caves are a taste of the Arctic closer to home.