An Israeli lifeguard has accidentally discovered an ancient artifact - while taking his regular morning swim. The Israel Antiquities Authority announced Sunday that the object the lifeguard turned over was a 2,500 year old, eye-shaped marble disc that was attached to ships to ward off the evil eye. Experts say the relic, discovered off the coast Palmahim beach in southern Israel where the ancient Yavne-Yam port city once stood, dates back to the 5th or 4th century B.C. The white disc, flat on one side and convex on the other, measures 8 inches (20 centimeters) in diameter. The center of the discus is perforated, and the remains of two circles are painted around its center. Archaeologists have turned up a wealth of artifacts in the same area.