"Based in Cusco, Alpaca Expeditions — self-styled the “Green Machine” and locally owned — is committed to sustainability and is highly rated for trekking, particularly Machu Picchu and the Inca Trail. They also offer alternative treks like the Salkantay (including five-day hikes around the Humantay Blue Lagoon or one-day options), treks to the seven lakes of Ausangate, a classic four-day Inca Trail hike for US$795, and a five-day Choquequirao trek for US$700." - Matthew Kepnes