Race the Sun: Is this five-sport, 182-mile Yorkshire relay the world's toughest race?

That's the challenge facing competitors who enter Race the Sun, an all-day, 182-mile endurance challenge that was held in North Yorkshire today.

It's a British Army event contested by soldiers, so it's not open to the public.

Entrants must complete 15 stages that encompass marching in full kit, running, swimming, cycling and kayaking.

Service personnel from all over the UK enter the race in teams, and overseas forces also send competitors.

What are the stages and route of Race the Sun?

- A 6km kayak leg along the River Ouse

- A 900m open water swim across the Great Lake at Castle Howard

- A 24km cycle and 6km run from Castle Howard to York

- A hill run up Sutton Bank

- A mountain bike leg through Cropton Forest to Levisham Moor

- A forced march with heavy pack to Rievaulx Moor

- A 3km stretcher race carrying a 40kg load to the finish, Imphal Barracks in York