What Is The Riddle Of The Sphinx?

The Sphinx, in Greek myth, was a hideous monster that caused death and devastation around the city of Thebes. It could only be overcome if someone could solve a certain riddle, which was: "What goes on four legs in the morning, two at noon and three in the evening?" This riddle was eventually solved by Oedipus, saving the city and becoming its king. The answer, whichmay not seem very difficult, is: a man. (A baby crawls (on four legs), a man walks on two, an old man uses a stick (three legs.)
However, the next time a plague struck Thebes, Oedipus wasn't so lucky, as this time it was said that the plague could only be stopped by revealing who had murdered the previous king. It turned out this was Oedipus himself, the king his own father and his present wife, his mother; so the story ended in disaster both for Oedipus and the city.