The most interesting Olympic game yet.
The world's first marathon for robots is underway in Japan where five androids are racing around a track.
But the knee-high robots pace is slow but steady and it's expected to take four days to find a winner.
The 26-mile course consists of 423 laps of an indoor track in the city of Osaka.
Operators are allowed to change the robots' batteries and motors but if the machines fall over they must get up by themselves.
The race is being organised by local authorities and a local robotics firm, which hopes the marathon will become an international event in the future.
Organizers say they expect the race to be won not by the fastest robot but by the one that can withstand the most wear and tear.