Around 36,000 runners took to the streets of the capital to take part in the London Marathon 2010.
But it wasn't all about speed. Thousands of runners dressed up to raise money for charity.
Princess Beatrice became the first Royal to run the marathon. She completed the course tied to 33 friends and dressed as a caterpillar!
Stamford the Chelsea football mascot looks pretty hot in his suit, but still completed the race for a children's charity.
Tsegaye Kebede of Ethiopia won the men's race running the 26.2 miles in 2 hours, 5 minutes and 18 seconds.
The women's race was won by Liliya Shobukhova from Russia with a time of 2 hours and 22 minutes.
It was Canadian Josh Cassidy's first attempt at the London Marathon. He won the men's wheelchair title in 1 hour and 35 minutes.
Tsuchida Wakako of Japan won the women's wheelchair race just a week after winning the Boston marathon.
This costume was definitely not designed to run a marathon in!
There were a lot of people with VERY achy legs at the end!