Eight thousand feet above sea level, this five-centuries-old pre-Columbian site was once home to the Incas. Until American historian Hiram Bingham publicized his findings of the area in a 1911 book called “Across South America,” the mountain-top ruins were widely unknown to anyone living outside of the Urubamba Valley and nearby Cusco. Since Spanish colonialists had no idea of Machu Picchu’s existence, its Incan architecture and design were preserved. There are two ways up to the “old peak,” by train or on foot. Unless you’re wildly adventurous — and don’t mind a two-to four-day massive hike up the Inca Trail — we recommend you go by rail, stay overnight in Aguas Calientes and take an early bus to the ruins to beat the crowds (and in the sweltering summer months, the sun).