There are four cycling events in the Olympic Games.
They are road, track, mountain biking and BMX.
These races are held indoors on a sloping track called a velodrome. The bikes used in track events have only one gear and no brakes.
In track events, the racing cyclists go around the velodrome many times. Each time they go around the velodrome is a lap.
In some events, two cyclists or two teams race each other. They start at opposite sides of the track and try to catch up with each other. In some track events the cyclists race for 1000 metres and the fastest one wins.
These races are on public roads. The bikes used in road races can have up to 14 gears and brakes. The cyclists ride about 190 kilometres through the countryside.
One road race is for teams and one is for single cyclists.
Mountain bike racing was added to the Olympic Games at Atlanta in 1996. Men and women begin at the same time but the men ride about 45 kilometres while the women ride about 35 kilometres. The men's race lasts approximately two hours and 15 minutes and the women's race lasts about two hours.