Around 35,000 people have taken to the streets of London to run 26.2 miles in the marathon. Millions of pounds are raised by the runners for charity.
Lots of celebs take part in the race too, including Katie Price and her husband Peter Andre.
Many of the runners wear costumes during the race. This man is getting ready to run, dressed as a chicken.
But it's not all about charity and silliness. It's a very big event for serious professional athletes too. Here the top women runners begin their race.
The women's winner was German runner Irina Mikitenko, on the left. British runner Mara Yamauchi had a brilliant run as well to finish in second place.
This is the start of the men's wheelchair race.
Which was won by Australia's Kurt Fearnley. It was a really close race as you can see, with Britain's David Weir finishing just behind him in second.
The men's race was extremely fast, with Kenya's Samuel Wanjiru leading the way here past the Houses of Parliament.
And Wanjiru held on for victory, in the quickest time ever seen in a London marathon, of two hours, five minutes and nine seconds.