Grab a seat (and oxygen mask) for a magnificent, dizzying ride up the Andes aboard Peru's legendary Tren Turistico. Reaching heights of over 15,000 feet above sea level, this railway whisks adventurous passengers through bustling Lima, past ancient ruins, and straight towards the clouds. For passengers, it's a once-in-a-lifetime trip, but for the conductor, crew, and even the train itself, it's a voyage that will push them to the limit as they confront steep inclines, fallen trees, and the crush of a city of 10 million people.