The old movie hall inside Phnom Penh’s Capitol Theatre, on Street 148, is now silent save for the occasional drip of water from the roof.

Gaining access to the building – which until three months ago was home to a dingy snooker bar, evinced by the fluorescent lights dangling awkwardly from its geometric-tiled ceiling – requires a bit of ingenuity. Nonetheless, the upper floors are littered with the remnants of past intruders.

The Capitol Theatre is one of a few dozen fading relics of Cambodia’s golden age of cinema scattered around the city. It was built in 1955, and renovated in 1967 by legendary architect Vann Molyvann. His modernist style is obvious in the theatre’s jagged – now leaky – roof.

In a few weeks, it will all be gone. The brightly coloured building is already surrounded with a corrugated metal fence and, according to the security guard manning the gate outside, the once-grand cinema will soon be razed to make room for a set of brand-new luxury condominiums.

“The construction workers will arrive in two weeks,” he says.

While perhaps the most recognisable, the Capitol is not the first of the golden-age movie theatres to be torn down. Just a few months ago, its neighbour, the Phnom Penh Cinema, was demolished. It belonged to the Ministry of Culture and Fine Arts, according to Ly Sokkhun, the Phsar Chas commune chief.

In what appears to be a race against urban development, a group of young architects have banded together to compile an archive of the theatres for future generations, dubbing the effort the Roung Kon Project – the Cinema Project.

“We know we cannot change it all, but we just want to make a document,” says Hun Sokagna, the de facto leader of the group of students and recent graduates. She says they aim to preserve a carefully constructed memory of the cinemas for the public, if nothing else.

The architects plan to include all they can dig up for the archive: old photographs, many of which circulate on the internet; written documents and antique maps; and re-drawn architectural blueprints, the most difficult piece of the puzzle, especially for the already destroyed theatres.

The group also hope to interview directors and actors of the era, like Dy Saveth, the 1960s silver screen star. They may as well ask a tuk-tuk driver: many are still able to navigate the blocks around Daun Penh by the cinemas’ old names with ease.

The theatres were always packed – hundreds of movies were produced in Cambodia in the two decades before Phnom Penh fell to the Khmer Rouge. They drew on traditional legends and characters, and made actors and musicians alike beloved by the masses. They made then-prime minister Prince Norodom Sihanouk an acclaimed director.

“It was planned as a cultural foundation, the cinema,” explains architect Pen Sereypagna, who is advising the group. “It was important to understand the city, and it was important to the identity of the city.”

The Roung Kon Project has already launched a website with a map of the sites that they have visited so far: 33 in total, though they guess that there are more.

Many have been converted into KTV bars or dens for squatters. There’s the Hemakcheat, a five-storey cinema on Street 130 that for the last two decades has been deeded out to poor families, newcomers from the provinces and drug addicts. Around the corner is the Lux Cinema, which is owned by the government, on Norodom Boulevard.

The Lux is the last of the old theatres still screening films, mostly low-budget horror flicks. It seems to operate with the same purpose as the Roung Kon Project: with an aim to preserve a small piece of the glitzy past, in its own way.

“We have kept the theatre open for so long because we want to preserve it for the young people,” says a manager at the counter. “The cinema was built a long time ago, and we don’t want to lose it all. It is the last one.”

Youk Chhang, the director of the Documentation Center of Cambodia, recalls wartime cinema fondly, even in the 1970s. Theatres were sometimes the targets of grenade attacks, he says, and going to a movie seemed an act of resistance.

“It was part of teenage life. When I drive past them in the city, it all comes back naturally,” he says. “The movies became much more interesting during wartime as well. It was really a form of resistance emotionally. They all stayed open.”

It is this sort of notion that Hor Daro, one of the young architects, would like to record. “It was the golden era,” he says. “We want to keep it, to show what happened during that time, how they lived.”

But the Lux is just as much of a physical relic as the crumbling cinemas. The forces that built it – a strong local film industry, and support for it – were casualties of the Khmer Rouge regime. None of the young architects has seen a film there, despite visiting it for their project.

Even Chhang wouldn’t return there. For him, the decorum has vanished, he says. “I tried to go back in the late 1990s to reconstruct my memories,” he says, stifling a laugh. “All I remember is that it was too loud, and people were urinating in the back of the cinema. I have not been back since.”