Tourists arrive at this storied Peruvian attraction by train, by bus, or even by helicopter. A few intrepid visitors attempt to reach the ancient city on foot via the Inca Trail. The Inca is actually made up of three intersecting trails, with most people taking the Classic Inca Trail, which requires a four- or five-day mountain trek. The great thing about this hike is that it passes through several different Andean ecosystems, making it possible for hikers to get a true look at the unique natural beauty of this part of South America. At the same time, unpredictable alpine weather and altitudes of more than 13,000 feet make the journey a hazardous undertaking. Altitude sickness is a common problem among hikers and fatalities are not unheard of (though people who know the symptoms and look out for them are usually able to avoid disaster by getting to lower elevations quickly). Guides and tour companies provide support for hikers who want to take on the Inca Trail, and some adventurers even opt to hire porters for the trip.