And they're off! This year, about 5,000 people took part in the race.
Parts of the race involve running through a field on fire. Real fire. The race consists of about 15 km of running and a similar length of obstacles.
Every year new obstacles are added to the track.
Crawling is a favourite Tough Guy activity: Here is the barbed-wire version.
One section involves swimming through freezing muddy water.
Of the 5,000 who started, almost 1,500 racers had to retire before the finish line.
Most of the runners are raising money for charity.
There is a section with smoke bombs.
This man is paying homage to Sacha Baron Cohen's Borat.
This cricket uniform looks like a severe handicap.
It's not just for "guys." Anyone of any age or gender can compete.
Crosses like these weigh about 40 kilograms, or 90 pounds.
This year, John Albion from Essex won the race, making it to the end in one hour and 39 minutes.
Tough Guy organises other races in April, July, and October, as well as a version for children.
Now it is time to relax in style ...
