Turtles All the Way Down

Source
To complete this Achievement, you have to fish up a from any high-level fishing pool. The achievement was only for Northrend in Wrath of the Lich King, and was later confirmed to be fished from Cataclysm-fishing pools as well when that expansion was released.

Inspiration
"Turtles all the way down" is a reference to the story of a conversation between a scientist and an old woman. The scientist, holding a public lecture on astronomy, was claimed by the woman to utter nonsense as the world was carried on the back of a giant turtle. This "World Turtle" is a religious myth which exists in Hindu mythology, Chinese mythology and Native American mythology. Asking the old woman what the turtle itself was sitting on, he was given the answer that it was sitting on another turtle. Asking what this lower turtle was sitting on, the woman apparently told him that it was "turtles all the way down".

While the story's origin and whether it actually happened or not is debated, it is in any case somewhat old and well-known.