You may do a double take when you hear of underwater chess, but it is a game and it has made its debut at a recent competition in London.
The game is the brainchild of Etan Ilfeld, who invented it back in 2012. He developed the rules and the special magnetic boards and pieces that allow the game to be played underwater.
The game keeps the standard rules of chess but adapts what the participants can do. Players have to dive down when it is their turn, assess the situation and make their move before they surface for air. Players are not allowed to use a breathing apparatus and can only breathe on the surface between turns.
Will underwater chess be the next big thing? Only time will tell.
You can check out a video of the latest championship below.