I returned last weekend from a memorable three-week tour of Peru, including a visit to Machu Picchu. With nearly 1 million visitors a year, Machu Picchu, an ancient Incan city nestled high in the cliffs of the Peruvian Andes, is one of the most acclaimed archeological sites in the world. Its sophisticated stone masonry and agriculture terraces are truly a sight to behold ... so much so that Machu Picchu is now listed by the World Monuments Fund as one of the world's 100 most endangered sites. Will all these visitors love Machu Picchu to death?