First you need to take a flight to Lima - Peru (South America). You will need another flight to Cusco (aprox. 1h30 hours), it is also possible to take a 23 hour bus ride on secondary roads. Once in Cusco the best option to reach the town of Aguas Calientes (base camp for exploring the lost city of the Incas) is by train. The train from Aguas calientes can be boarded  from 3 stations, depending on your travel plans, Poroy station (3h15 minutes), Urubamba station (2h30 minutes) or the Ollantaytambo station (2 hours). Finally the more adventurous traveller can take an overnight bus-taxi combo followed by a 10 km. hike if they do not want to take the train.