Relay races emerged in the United States in the 1880s as a variation on charity races between firemen, who would hand a red pennant on to teammates every 300 yards. There are two very common relay events: the 4×100 metres relay and the 4×400 metres relay. Both events entered the Olympic programme at the 1912 Summer Games after a one-off men's medley relay featured in 1908 Olympics. The 4 × 100 m event is run strictly within the same lane on the track, meaning that the team collectively runs one complete circuit of the track. Teams in a 4 × 400 m event remain in their own lane until the runner of the second leg passes the first bend, at which point runners can leave their lanes and head towards the inner-most part of the circuit. For the second and third baton change overs, teammates must align themselves in respect of their team position – leading teams take the inner lanes while teammates of the slower teams must await the baton on outer lanes.