There really is no better way to fully appreciate the grandeur and complexity of Machu Picchu than taking a tour with an expert guide. They will lead you on a logical route throughout the site taking in the key areas, explaining as they go some of the theories around the citadel, and pointing out Inca terraces and pathways as well as sacred stones and remnants of homes and temples. The site is incredibly well-preserved (the Spanish invaders never made it this far into the mountains) so there will be countless opportunities to take some great photos, but the guides can also recommend particularly good viewpoints depending on how far you would like to walk or climb.