Machu Picchu, also known as the "Lost City," is home to the ruins of Peru's Inca Empire and was rediscovered in 1911. Although it stands quite high in the mountains at almost 8,000 feet above sea level, it is still facing erosion, landslides, and a high influx of visitors.
UNESCO and Peru set a limit of 2,500 visitors per day, but with millions of tourists per year, the amount of daily visitors greatly exceeds that set limit. Unless more regulations are put in place, the 15th-century ruins at Machu Picchu may soon collapse. Make sure to get there before the ruins are ruined!