The Sunless Sea was a great subterranean lake that lay under the land of Narnia in the Shallow Lands of Underland. The northern-most area of the Sunless Sea served as a seaport and was known as the Pale Beaches. All outlets to the Overworld lay on the other side of the Sunless Sea (to the south), with the exeption of the secret tunnel dug by the Earthmen (under the spell of the Lady of the Green Kirtle in preparation to invade Narnia). The Sunless Sea, along with the whole Underland were unknown to the surface world until the capture of Rilian. After the return of Rilian, Narnians would go on boating trips on the sea and tell each other stories of the land of Bism (which lay some six thousand feet below even the Shadow Lands).