Watch triathletes from around the country and the globe take on an athletic challenge of a 70.3-mile triathlon. Athletes kick off with a 1.2-mile protected open water swim through the Choptank River, then a 56-mile flat bike through the Blackwater National Wildlife Refuge. They end with a 13.1-mile run. The transitions and finish line all happen at Gerry Boyle Park at Great Marsh in Cambridge, Maryland – a great spot for spectators.