Most people struggle to run 10km. The London Rat Race somehow corrals large groups of Londoners to not only run but jump, swim, kayak and climb the distance and all for a good cause - Shelter. The acquatic obstacle course starts inside the ExCel centre, with participants will facing a quick fire barrage of obstacles before they head out on to the dockside. From there, there's a short run west towards the Emirates Air Line before they have to plunge into the Royal Victoria Dock. Next up is a short swim, followed by a thigh-deep wade to an urban beach. Back on dry land and heading east there's a mix of jumping, swimming and wading. Then more running before a kayak section and an equally challenging homeward leg. All the time avoiding the giant inflatables and plaunging down the 50ft waterslide.