This incredible Incan citadel is set high in the Andes Mountains above the Urubamba River valley in Peru. They were built in the 15th Century and then later on abandoned, and have since become an exotic travel destination. Renowned for sophisticated and intricate dry-stone walls that have fused giant blocks together, seeming impossible without the use of mortar. These fascinating buildings boast astronomical alignments and incredibly picturesque panoramic views in a mystical and other-worldly manner. You can visit this incredible sight on a tour to Peru.