Many modern-day archaeologists now believe that Machu Picchu served as a royal estate for Inca emperors and nobles. Others have theorized that it was a religious site, pointing to its proximity to mountains and other geographical features that the Incas held sacred. Dozens of alternate hypotheses have cropped up in the years since Machu Picchu was first unveiled to the world, with scholars variously interpreting it as a prison, a trade hub, a station for testing new crops, a women’s retreat or a city devoted to the coronation of kings, among many examples.