Huayna Picchu offers an exhilarating and challenging ascent next to Machu Picchu, rewarding hikers with unparalleled panoramic views of the ancient citadel and surrounding landscape. Accessibility is limited, requiring a separate, highly sought-after permit booked months in advance, with only 400 daily spots split into specific entry times; the steep, narrow trail is not suitable for those with mobility issues, extreme fear of heights, or children under 12, and is certainly not wheelchair accessible. While a guide isn't mandatory for the hike itself (assuming you have a Machu Picchu guide), many incorporate it into their overall tour. The cost is an additional ~$40-50 USD on top of the Machu Picchu entrance fee, and the hike typically lasts 2-3 hours round trip, independent of your Machu Picchu visit. Best visited during the dry season (May-October) for optimal trail conditions, it's crucial to be acclimatized to the high altitude and come prepared with water, appropriate footwear, and sun protection.