Angkor was long an unknown “wonder of the world,” said Ellen Creager in the Detroit Free Press. The mysterious complex of ruins outside modern-day Siem Reap, Cambodia, is as stunning as the “pyramids of Egypt or the temples of Maya” and as prodigiously complex as Mexico’s Chichen Itza or Peru’s Machu Picchu. More than 70 temples are scattered across the 1,000-square-mile sprawl. But the onetime capital of the Khmer empire, now a UNESCO World Heritage site, for centuries remained a secret from the rest of the world.

Angkor’s rise and fall is “dramatic enough to fill 10 history books.” Between the 12th and 15th centuries, the Khmer empire spread to encompass what are now the countries of Laos, Vietnam, Thailand, and Cambodia. But in the 15th century, the Khmers were forced to abandon their capital, after a series of Siamese attacks left the land ravaged. For the next five centuries, the ancient city lay hidden under the wild jungles of central Cambodia. “While nations rose and fell, while America was built,” Angkor stood forgotten. Only in the late 19th century did French archaeologists uncover it and begin to restore many of the tumbledown ruins.

Cambodia’s prime tourist attraction is Angkor Wat, an imperial structure built by King Suryavarman II in the 12th century in honor of the Hindu god Vishnu. Constructed with “porous clay foundations and sandstone exteriors,” its five towers are “stacked like a Jenga puzzle, each piece fitting atop the other.” Nearby sits another temple, Bayon, built a few decades later by King Jayavarman VII. Its 49 towers have been adorned with “200 or more” smiling stone faces. Yet another temple, Ta Prohm, looks much as it did when it was unearthed in the 1900s: “Giant kapok tree roots winding through the doors and windows” make it seem less a work of man than a “part of the natural landscape.” Angkor may have been forgotten for centuries, but treasures like these will ensure it is celebrated for generations to come.