Sheldon mentions that "a prohibition against looking is well established in heroic mythology; Lot and his wife, Perseus and Medusa, and Orpheus and Eurydice..."
*Lot's wife turned to a pillar of salt after turning around to look at the city of Sodom as it burned (she and her family were told to leave and not look back).
*Perseus was the only one to not turn to stone after looking at Medusa.
*Orpheus was a hero in Greek mythology who made beautiful music and tried to save his wife, Eurydice from the Underworld. She was allowedto return with him to earth on one condition: he should walk in front of her and not look back until they both had reached the upper world. He set off with Eurydice following, and, in his anxiety, as soon as he reached the upper world, he turned to look at her, forgetting that both needed to be in the upper world, and she vanished for the second time, but now forever.