St. Mary's Lighthouse, Whitley Bay, England
St. Mary's Lighthouse sits on an island reachable from the mainland only by a concrete causeway between tides. During high tides, the causeway is completely submerged. The 120-foot-high lighthouse lies north of Whitley Bay, and though the lighthouse is no longer active, the site remains a popular tourist attraction. Visitors can climb the 136 lighthouse steps to the lantern room, or visit a small museum, visitor's center and cafe.