Selfies are the dangerous downside of the huge crowds seen on the Tour de France, according to some of the riders.
As the Tour moves south from Yorkshire to Cambridge, competitors have warned of the potential risks to spectators who choose to stand in the road with their backs to the speeding peloton.
Geraint Thomas said: "It's the new pain in the arse."
The Team Sky rider added: "The worst thing is when people have got their back to the peloton taking selfies. There were a few. They don't see us coming, they're stood in the road and it's dodgy. If you want to do that, stand on a wall or something.
"I think people need to realise we take up the whole road. If you want to go and do that, go and sit in a tree. There's not much racing on British roads and people don't understand how fast we're going and how close we get.
"There have been too many accidents with riders hitting spectators, we don't want to see that but it could easily happen."
BMC Racing's Tejay van Garderen Tweeted: "Standing I the middle of the road with you back turned while 200 cyclists come at you, just to take a selfie. #think." (sic)
The American also posted: "That being said, I love the crowds and thank you for your support. But please give us room."
Yesterday, Swiss rider Fabian Cancellara said on Twitter: "Huge crowds are amazing for us bike riders but let's try to keep it safe for everyone and make more space."
The Trek Factory Racing rider added: "To all media, send out the message the fans should stand 1 meter back on the road when we pass with 50km/h. #dangerous."
Australian Rickie Porte told the Sydney Morning Herald: "Many of the riders were saying they had never raced before such masses of people, especially climbing up the Cote de Buttertubs midway into the stage.
"However, at the same time, with the crowd 10 deep in places, it was dangerous at times with so many people taking selfies getting in our path."
Police have also warned spectators to be careful, following images of crowds getting extremely close to riders on some of the climbs.
Yesterday, a teenage boy had to be airlifted to hospital with serious leg injuries after he fell from the roadside in Ilkley into the path of a Tour team vehicle that was following behind the race.
He was flown to Leeds General Infirmary and is in a stable condition after undergoing surgery.
Officers said it appears to have been an "unfortunate accident".
There were no injuries reported today.