More than 200 paintings adorning the walls of the massive, 12th Century Cambodian temple Angkor Wat were discovered hiding in plain sight, after Noel Hidalgo Tan, a rock-art researcher at Australian National University in Canberra, noticed traces of red paint on the walls of the religious monument.
Photo Credit: Bjørn Christian Tørrissen via Wikimedia Commons
Angkor Wat sees millions of visitors every year. How did the murals manage to go unnoticed for so long? Simply put: They were hard to see. The traces of pigment spotted by Tan – an expert – were difficult to spot in the first place, and basically impossible to make heads or tails of with the naked eye. So he uploaded the images to his computer. Using a technique called decorrelation stretch analysis (widely employed in the study of pictographs, and used by NASA to study photos of Mars), he was able to "stretch" (i.e. enhance, or exaggerate) subtle color-differences in his photographs, bringing the faded colors of the murals into clear, unambiguous view. Via LiveScience:
The digitally enhanced pictures revealed paintings of elephants, lions, the Hindu monkey god Hanuman, boats and buildings — perhaps even images of Angkor Wat itself.
One chamber in the highest tier of Angkor Wat's central tower, known as the Bakan, contains an elaborate scene [pictured above] of a traditional Khmer musical ensemble known as the pinpeat, which is made up of different gongs, xylophones, wind instruments and other percussion instruments. In the same chamber, there's an intricate scene featuring people riding horses between two structures, which might be temples.