In the swamps of the town of Lerna, to the south of Tiryns, there lived a Hydra, a nine-headed monster which terrorized the inhabitants of the area. It is said that this creature was raised by Hera in order to intimidate Hercules. This beast was so deadly that his breath could kill. Athena, the goddess of wisdom and war, came to Hercules and advised him as to how to defeat the Hydra. She told Hercules that he must force the Hydra out of its lair by shooting flaming arrows into it and setting it afire. This way he would be able to keep the Hydra within his sights. She told him that the center-most of the nine heads was immortal.
Hercules was accompanied to this labor by his nephew Iolaus, the son of Iphicles. He was a charioteer and often accompanied his uncle on his journeys. Iolaus also helped by lighting on fire the arrows which went into the Hydras den. As the Hydra came out. Hercules surprised it and lopped off one of its heads. To his surprise, two more grew in its place. He lopped off several others only to find the same result. Hercules then asked Iolaus to sear or burn the place where the cut-off head had been to prevent two more from growing in that spot. The trick was successful until only the center head remained. By some accounts, Hercules used a golden sword to cut off that immortal head. When he removed the final one, he buried it under a heavy rock while Iolaus seared the neck. Hercules then dipped his arrows into the Hydras gall which rendered them deadly poisonous. When he returned to Tiryns, Eurystheus told Hercules that this labor did not count as one of the ten he was obliged to fulfill because he had the help of Iolaus in accomplishing it. He still had nine labors to complete.
At some point during the discussion of this particular story, it would be important for the children to find out what a hydra is and where it is found in the world today. This incorporates some science facts and inquiry (are hydras poisonous?) into a humanities based unit. Similarly, the other labors which involve animals can be expanded to include some research into the creatures which Hercules encounters. There are no lions in present day Greece, yet our hero battled many of them in this ancient tale. Is it possible that there were once lions in Greece and, if so, was it the climate or civilization which drove them out?