Centuries of wave action, freezing, and thawing have sculpted shorelines throughout Apostle Islands National Lakeshore. Some of the Great Lakes' most spectacular scenery occurs where these forces interact with sandstone of the Devils Island Formation to create extensive sea caves. Nature has carved delicate arches, vaulted chambers, and honeycombed passageways into cliffs on the north shore of Devils Island, Swallow Point on Sand Island, and along the mainland near the Lakeshore's western boundary. People come to Apostle Islands National Lakeshore in summer and winter to visit the sea caves an