Today's Geo Quiz lies at the bottom of a sea. Just about everyone's heard the story of the sinking of the Titanic.
That happened in the North Atlantic in 1912. Well, today we're looking for the final resting place of Titanic's sister ship.
It was the Britannic -- a famous World War One hospital ship. She sank near Greece, after striking a German mine in 1916.
The question is, what sea did the ship sink into?
The BBC's Malcolm Brabant offers up some clues.
â€œThis wreck lies off the southeastern tip of the Greek province of Attica which is the part of the country which contains Athens; it's very close to an island called Kea in about 400 feet of water.â€
So which sea surrounds the Greek island of Kea?
We'll chart those waters in just a minute...