man in gray jacket standing on rocky hill during daytime

Today the Classic Inca Trail to Machu Picchu - which, as part of the Machu Picchu Historical Sanctuary, has been designated a World Heritage natural and cultural site is the most important and most popular hiking trail in South America, followed by many thousands of ecotourists and modern-day pilgrims in the past 3 decades. Its extreme popularity in recent years -- more than 75,000 people a year hike the famous trail -- has led to concerns among environmentalists and historians that the trail is suffering potentially irreparable degradation.