The purpose of the Incan site of Machu Picchu, built during the 15th century, is not known. Some argue that it was a royal retreat, while others believe it had a more religious purpose. One theory holds that Incan pilgrims would travel there to symbolically retrace the story of their ancestors. The site is surrounded by a sacred river and revered peaks. Certain buildings and stones seem to line up with the sun on significant dates, and may have been the sites of sacrifices and other rituals. Matija Grguric built this LEGO version.