Robots have raced against humans in a half-marathon for the first time. Some 21 humanoid robots raced alongside thousands of runners around the 21km (13-mile) course in Beijing, China, on Saturday. Some of the robots that took part were as short as 3ft 9in, while others were as tall as 5ft 9in. They had to resemble humans and be able to walk or run - wheels were not allowed. Image: Several robots joined the race. Pics: Reuters 'I don't want to boast, but...' The winning robot was Tiangong Ultra, which crossed the finishing line with a time of two hours...