Around 15,000 runners have followed in the footsteps of Mo Farah and Jessica Ennis - by crossing the finish line in the Olympic Stadium!
It was for the National Lottery Anniversary Run, a special race around the Olympic Park that ended in stadium.
The main race was five miles long, and there was a shorter 1.5-mile family run for children.
It was the first public event in Olympic Stadium since the end of London 2012.
Olympic champions Victoria Pendleton and Nicola Adams took part in the run - and Sir Chris Hoy started the race.
Sir Chris said: "It is a huge honour to start it and it gives me a great excuse not to show everybody my lack of running ability in front of thousands of people."