London mayor Boris Johnson described the capital as having "one of the greatest cycling events in the world" as he took to the saddle to complete a gruelling 100-mile road race.
Mr Johnson, who battled with a puncture to complete the challenge in just over eight hours, was taking part in one of a number of events this weekend in what was billed as the UK's largest festival of cycling.
Speaking on the finish line on The Mall, Mr Johnson said: "This is a great day for cycling, and for this city.
"I want to thank the organisers and the wonderful crowd who made all the difference as we cycled by, helping to spur me on to finish the gruelling 100 miles in a respectable eight hours.
"Huge congratulations to everyone who took part - RideLondon is now firmly on the map as one of the greatest cycling events in the world."
Among the 16,500 people taking part in the race, which took cyclists on a route out of the capital and into the Surrey countryside, were other famous faces including Rugby World Cup winner Matt Dawson and Olympic champions James Cracknell and Sally Gunnell.
Cracknell was the first celebrity over the finish line with a time of just over four hours and 36 minutes.
"It was brilliant," he said afterwards.
"Apart from my time, the best thing was the fact that there were thousands of people flooding into the Olympic Park, not to watch something, or see top performers, but to do something themselves.
"If there are any legacy discussions going on, that is the selling point for me - nearly 20,000 people riding out for 100 miles. I can really see this being like the London Marathon."