This painting by Carle van Loo features an especially nasty-looking sea monster! You can see Perseus arriving on his winged sandals, ready to do battle with that monster in order to free the princess Andromeda who has been left as a sacrificial offering. Perseus manages to slay the monster and then takes Andromeda as his bride.
You can also find more myths and legends for the week of May 13-19 here. For more information and links to the actual javascript code, see the Myths & Legends Widget Reference Page.