"When I visited Machu Picchu I felt safer there than in most other parts of Peru; it's such a common tourist destination that you'll likely be hiking with a group or in crowds, so pickpockets and petty thieves are less likely. The bigger concerns are health-related: bring plenty of water, use sunscreen and a hat, and take altitude sickness seriously—stay in Cusco for a couple of days to acclimatize if you can. If you hike, use a licensed guide, since unlicensed guides can take you the wrong route or keep your hiking-permit payment." - Matthew Kepnes