RENEE MONTAGNE, HOST: And there are a lot of words we're using to describe this winter of the polar vortex: brutal, unrelenting - that's a couple - but how about stunning? The deep freeze has brought great beauty to a group of islands way up north floating in Lake Superior.
(SOUNDBITE OF CRUNCHY FOOTSTEPS)
DAVID GREENE, HOST:
They're called the Sea Caves of the Apostle Island. They're right off the shore of Wisconsin. And in the summertime, kayakers paddle in and out of these sea caves.
MONTAGNE: In a winter that is cold enough, one can strap on snowshoes and trek over the frozen lake to visit the caves. Imagine this: a stiff wind and bone-deep cold. You walk and walk a
