Combine two of the most common materials found on the surface of our planet - dirt and water - and you get mud, which, in turn, can be played in, struggled through, rubbed on for medicinal value, or just worn for fun. Collected over the past few months from festivals sporting events and more, you'll find here photographs of people around the world playing with, wallowing in, wearing and just dealing with mud - one of the filthiest entries on the Big Picture to date. ( 31 photos total