Located off Wisconsin's Bayfield Peninsula, the Apostle Islands are accessible by private boat and by a regular schedule of cruises run by the Apostle Islands Cruise Service out of Bayfield. This cluster of 21 islands were exposed by retreating glaciers during the last Ice Age. Characterized by sand beaches, dense forests, sandstone cliffs and sea caves, the Apostles offer sailing, hiking and kayaking in summer and a variety of winter pastimes for those adventurous enough to cross the ice. Six historic light stations built between 1857 and 1891 still mark the outer islands, and park staff conducts interpretive programs at several of them. The park also includes 12 mainland miles along the northwest coast of the peninsula at Little Sand.