Machu Picchu, a breathtaking ancient Inca citadel, is accessible primarily via scenic train routes from Cusco or Ollantaytambo to Aguas Calientes, followed by a bus or hike up to the site; multi-day treks like the Inca Trail also lead here. A licensed guide is mandatory for entry, so solo exploration of the ruins is not permitted, but independent travel to the area is common. The site is open year-round, though the rainy season (November-April) can impact conditions, and the Inca Trail closes in February. Costs are substantial, typically ranging from $300-$1000+ per person for transportation, entry, and guiding services, depending on travel style and duration. A typical visit to the main site lasts 3-4 hours, with an additional 2-4 hours if hiking one of the surrounding mountains. It's crucial to book train tickets and entry passes (especially for peak season or mountain hikes) well in advance, and allow time to acclimatize to the altitude in Cusco beforehand.