in Greek mythology (= ancient stories), the stables (= buildings for keeping horses or cows) of King Augeas, which had never been cleaned until Hercules was given the task of cleaning them

Hercules' fifth labour was to clean the Augean Stables in a limited time. 赫拉克勒斯的第五项功绩是在有限的时间内清理奥革阿斯的牛圈。