In the spring of 1943, during the Sino-Japanese War, photographer James Lo and his wife Lucy Lo ventured to a set of remote, nearly abandoned caves near where the ancient northern and southern Silk Road trade routes converged, at the nexus of China and Central Asia. There were 700 carved spaces in the face of a cliff, known as the Mogao Caves. Among them, some 500 were profusely decorated with sculptures and murals, remarkable examples of Buddhist art that span 1,000 years. Today, the caves’ 2,000 painted sculptures and nearly…