While the Fifa World Cup in Brazil might be throwing up the odd instance of 'dirty' play, an event in Germany is taking that concept to a whole new level.
The Wattolümpiade, or ''Mud Olympics'', takes place in Brunsbüttel, a town in the north of Germany that lies on the mouth of the Elbe river, near the North Sea.
Participants compete in football, handball and volleyball matches, among other events, on the river's intertidal zone, its website says.
The Wattolümpiade took place on July 6 this year.
Founded in 2004 by painter and sculptor Jens Rusch, the Mud Olympics are a charity event raising funds for cancer relief.