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In this photo taken on May 11, 2011, a Western tourist sits on the top of the 10th century temple Bakheng in the Angkor Wat complex near Siem Reap, Cambodia, to view the setting sun. A traffic jam of up to 3,000 tourists surges up a steep hillside, trampling over vulnerable stonework and quaffing beer at a sacred hilltop that provides spectacular sunset views of the massive beehive-like towers rising from the main temple in this ancient city: Angkor Wat. Cambodian Tourism Minister Thong Khon says some 6 million visitors per year are projected by 2020. (AP Photo/David Longstreath)

In this photo taken on May 11, 2011, a Western tourist sits on the top of the 10th century temple Bakheng in the Angkor Wat complex near Siem Reap, Cambodia, to view the setting sun. A traffic jam of up to 3,000 tourists surges up a steep hillside, trampling over vulnerable stonework and quaffing beer at a sacred hilltop that provides spectacular sunset views of the massive beehive-like towers rising from the main temple in this ancient city: Angkor Wat. Cambodian Tourism Minister Thong Khon says some 6 million visitors per year are projected by 2020. (AP Photo/David Longstreath)

Mystery of Angkor Wat

One of the ancient world's lingering mysteries has been solved.