monitor the conditions there.]]> routes that connected Europe and Asia.]]> threat to the Mogao Grottoes in northwestern China.]]> bulky backpacks and hot, humid breath, the tourists represent a real threat to the Mogao Grottoes in northwestern China.]]> Principles filled a key gap.]]> imagination much to see what might happen in the future," Agnew said.]]> calculate just how many sightseers the cave complex could handle each day.]]> conservationists at the Getty have been working to conserve, or protect, the caves.]]> survey the caves, to examine them carefully and understand the materials used to make the paintings.]]> conserve, or protect, the caves.]]> ancient Chinese clothing, dance, musical instruments, wrestling, polo, archery and even a sport known as "elephant lifting."]]> conditions there.]]> expert on caves, has been visiting Dunhuang since the late 1980s - more than 50 times overall.]]> determine the threats - like damage from sand and high humidity.]]> extensive trade routes that connected Europe and Asia.]]>