Los Angeles’s Getty Conservation Institute is teaming up with China’s Dunhuang Academy to preserve the Mogao Grottoes, a series of hand-hewn Buddhist caves carved out of cliffs in the Gobi Desert between the 4th and 14th centuries. According to the Los Angeles Times, new measures have been developed to combat a modern threat to the survival of these ancient marvels: an influx of tourists.

Nearly 500 caves exist at the grottoes, each decorated by monks or by pilgrims and merchants traveling along the Silk Road as early as 1,700 years ago. They also contain ancient sculptures, such as a 100-foot-tall, 1,300-year-old Buddha, and a library of Buddhist manuscripts. After surviving earthquakes, floods, foreign looters, and Russian soldiers who sheltered within their walls while fleeing the Bolsheviks, the caves are facing their greatest threat yet from modern tourists.

The Mogao Grottoes face similar issues to another UNESCO World Heritage Site, Spain’s Altamira Caves, which were forced to close to the public in 2002 over concerns that hordes of tourists were damaging the prehistoric paintings with their body heat. It has only now reopened on a temporary, limited basis (see “Spain Will Keep “Sistine Chapel of Palaeolithic Art” Open to the Public“).

The Chinese site now sees an unsustainable nearly 1 million annual visitors, up from only 26,000 when it first opened in 1979.  Thanks to a 25-year-old partnership with the Getty (the institute’s longest-running project), Dunhuang Academy has new guidelines in place to protect the caves while welcoming tourists.

This month, a new $50-million visitor center designed by Beijing architect Cui Kai opened, featuring two movie theaters that show two 20 minute films. High resolution footage of seven of the caves (painstakingly captured over seven months and edited for two years), provides an immersive experience to the viewer. Consequently, visitors spend less time inside the caves themselves.

The conditions inside the grottoes are being carefully monitored, with the Getty studying the effect of temperature, humidity, and crowd size. Up to 6,000 tourists can now visit 8 to 10 of the caves daily, provided they have advance reservations.

“You can go in, reattach some paint flakes and go home, but that’s really not particularly useful,” Tim Whalen, director of the Getty Conservation Institute, told the Times. “These are questions facing World Heritage Sites everywhere—how do you preserve them and still ensure access for the public and scholars?”

The Getty Museum in Los Angeles will also look to entice Western travelers to Dunhuang—which currently attracts a mostly domestic crowd—through a 2016 exhibition that will describe the preservation efforts and feature cave replicas along with artifacts and relics from the site.