In Greek mythology, Sphinx was a female mythical creature, which had the head of a human, the body of a lion, the wings of an eagle and the tail of a serpent. She was daughter of Orthus (a monster dog with two heads) and most likely Echidna (half woman – half snake). According to the myths, she dwelt outside the city of Thebes, and asked an unsolved riddle to all travellers, in order to let them pass: “what has four legs in the morning, two legs in the afternoon, and three legs at night?” Anyone who could not answer was killed. However, a wise young prince, named Oedipus, answered "the human", who crawls on all fours as a baby, walks on two as an adult, and needs a walking cane, when old. His answer frustrated the Sphinx, killing itself in despair.