The Lightship Overfalls is one of seven remaining lightships open to the public in the U.S. of the 179 that were built between 1920 and 1950. Lightships were floating lighthouses that aided in nighttime navigation, warned mariners in fog and offered radio beacons for longer-range identification. Guided tours are available on Sundays, Mondays, Thursdays, Fridays and Saturdays from10 a.m. to 3:30 p.m. between Memorial Day and Labor Day. Adults pay $5 for a tour, while children 12 or younger can take the tour free of charge. The Lightship Overfalls is located at 219 Pilottown Road in Lewes.