Incan citadel of Machu Picchu, Peru

Machu Picchu, one of the new seven wonders of the world, is an Incan citadel set high in the Andes Mountains in Peru, above the Urubamba River valley. Built in the 15th century and later abandoned, it’s renowned for its sophisticated dry-stone walls that fuse huge blocks without the use of mortar, intriguing buildings that play on astronomical alignments and panoramic views. Its exact former use remains a mystery.

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