11 of 99:
These are photos from the Tough Mudder competition, which was run in Austin April 20 and 21, 2013. The Tough Mudder is a hardcore obstacle course designed by British Special Forces. It's typically between 10 and 12 miles and challenges competitors with obstacles such as 12-foot walls and underground tunnels. More about the course on ToughMudder.com.
( Photo / ABC-13/Mario Segura)