Firefighters from around the world gathered in downtown Chengdu to take on one of the toughest challenges at the World Police and Fire Games: the stair race. It's a test of pure strength and endurance as our Tang Bo reports.

Rachel Bracken came all the way from Ireland to watch her dad compete in the stair race. Her father is a firefighter from the Dublin Airport Fire Service. It's his second time doing one of these brutal climbs.

Over 300 athletes from around the world, including 68 female firefighters, participated in the climbs at Chengdu's Yintai Center. All participants were required to put on their 30-kilogram air tank, climbing 53 floors with an elevation of 220-meters. According to the rules, competitors can travel up the stairs taking as many steps at a time as they want. Slower ones will have to give the way on their right side to any competitor who is catching up. When they reach the finish line, the exasperation says it all.