King Augeas assigning Heracles to clean the Augean stables.
Heracles is disgusted and humiliated by the task given to him.
He was assigned the impossible task of cleaning these stables, it was impossible because they never stopped producing dung. He did it rerouting the rivers of Alpheus and Peneus to wash out the filth.
King Augeas promised Heracles 1/10 of the cattle if he cleaned the stables in one day and he did it. But then didn't give him the cattle because he said that Eurystheus had assigned him to do it anyway.
Augeas banished him and he returned and Heracles slew him and gave his kingdom to Augeas' son Phyleus.
After he slew Augeas, Heracles founded the olympic games.