Machu Picchu © Brian Snelson
The ancient Inca citadel of Machu Picchu is regarded as the most significant archaeological site in South America, perched high in the Andes. Fortunately, Spanish colonists didn't discover and destroy the structure, as it's completely concealed from below. The site is surrounded by grazing llamas and steep agricultural terraces, and consists of a central plaza, towers, palaces and water canals, as well as ornate fountains and a sacred ceremonial area of royal tombs and intricately carved temples. The sacred Temple of the Sun is one of the site's highlights, with the mountain of Huayna Picchu forming a dramatic backdrop to the city.