Skateboarders soar out of the concrete bowl beneath London's Southbank Centre, as they have done for the past 40 years, while spectators drink beer and hiphop beats stoke up the party atmosphere.
But this is no party -- it's a protest. These knights of the pavement are jousting with authorities to save one of the world's most iconic skateparks from being converted into a stretch of chain stores and cafes.
"It's world renowned. People literally come all the way from America or Europe just to see this place," says Henry Edwards-Wood, 25, a professional skateboard cinematographer and spokesman for the "Long Live Southbank" campaign.
To support their campaign skateboarders held a three-day "jam" over the May bank holiday weekend and have launched an online petition which has gathered more than 28,000 names from across the globe.
And this clash between counterculture and consumerism is also going legal. Lawyers acting for the Long Live Southbank campaign have filed an application to protect it as a community space in the way that Britain's famed village greens are sacred.
"This is a big tourist attraction for people who come to London. Who's going to come here to see a Starbucks or another Wagamamas?" said Edwards-Wood, as skateboarders in hoodies and backwards baseball caps whizzed past.
The dingy "undercroft" where the skateboarders are based sits beneath the brutalist Southbank Centre on the River Thames, home to renowned arts venues such as the Hayward Art Gallery, the Queen Elizabeth Hall, and Purcell Room.
In the 1970s it became the birthplace of skateboarding in Britain and has since won a name as a mecca for skaters around the globe, featuring in numerous videos and in the best-selling computer game Tony Hawk's Pro Skater 4.
It has also provided a refuge for BMXers and graffiti artists.
Earlier this year, however, the Southbank Centre unveiled plans for a new Festival Wing which would involve the destruction of the undercroft and the building of a new skatepark under a nearby bridge.
The £120 million ($186 million, 142 million euro) facelift includes new space for performances and exhibitions and has special arts facilities for young people.
Southbank Centre Director Mike McCart says the spot now colonised by the skateboarders is a prime location for cafes and restaurants -- the rent from which would fund the plan.
"If we're unable to use commercial retail in this location it would fundamentally undermine the project as a whole," he said.
McCart said the proposed new site under the Hungerford Bridge about 200 metres (yards) along the river would be the same size and area as the current spot.
"We've kept it absolutely raw, so it's a found space very similar to the ones the skaters inherited in the Seventies."
The leader of Lambeth council, Lib Peck, said they would "like to see skateboarding kept on the South Bank".
"We are confident that a satisfactory solution can be found," Peck said.
But the Southbank skaters are not giving up without a fight.
At the jam on the first weekend of May, hundreds of tourists and passersby lined up behind the fences that surround the skating area to watch a skateboard contest, while music blared over a sound system.
Volunteers sold black and white "Long Live Southbank" T-shirts and cupcakes to raise money for the campaign. Skaters gave beginners lessons to children and adults alike -- making sure their pupils put on the safety helmets that they themselves refuse to wear.
As night fell it got nostalgic with classic skate movies shown on a big screen and photos of Southbank from the 1970s to the present day taped to a wall.
Nick Jensen, a professional skateboarder who has frequented Southbank for years, said it was a "mecca for skateboarding".
"It's like threatening to take a part of your upbringing or part of who you are away," he said of the closure plan.
Their campaign has won heavyweight support at home and abroad.
British lawmaker and former culture minister Ben Bradshaw said he was "really sad" at the plan to close the "iconic cultural landmark in London" while respected broadcaster and journalist Libby Purves wrote in The Times newspaper that to replace the skate spot to build more shops and cafes would be "cultural vandalism."
Mark Gonzales, an American professional skateboarder and artist named the most influential skateboarder of all time by Thrasher magazine, the industry bible, called for the preservation of the spot.
"It's a place where skaters from all around the world can go and they can meet other skaters from other countries," he said in a video statement for the campaign.
Tom "Blondey" McCoy, a 15-year-old sponsored skater, said that building a new park nearby as the Southbank Centre had suggested would not have the same "vibe."
"It's just a completely irreplaceable thing -- and the way I see it retail is the most replaceable thing," he said.
"It's as important to us as a part of our lives as our homes."