The Inca Trail is a 3-day trek that takes you from Cuzco to Machu Picchu. First of all, you should know that it's quite hard, because of the height. Another option is to take a train to Aguas Calientes, spend the night and the next day you can climb, walk or take a bus to the Inca ruins of Machu Picchu. If you decide to walk, stay 2-3 days in Cuzco first, to acclimatize, and not get altitude sickness. Take coca tea or chew coca leaves to help you withstand the altitude. If you get sick, do not continue, go down, save the climb for another time. The Inca trail is on the old road leading to the lost city.