This guide is based on a mixture of our first hand experience of trekking the Classic Inca Trail plus useful advice from friends and other sites on the web. Our trek was organised by G Adventures and I would highly recommend them, everything about the trip was excellent, our guides, chef and porters were amazing. The Classic Inca Trail is a 4 day trek starting at Km82 and finishing at the Lost City if the Incas, Machu Picchu, at sunrise on the 4th day. The trek is rated moderate and any reasonably fit individual should be able to complete it. Having said that we found this to be one of the most physically challenging things we have ever done. This was mainly due to the Altitude, the highest point "Dead Womans Pass" is 4200m above sea level, the air is thinner at this height and makes breathing more difficult.
From Puno we went to explore Lake Titicaca, the highest freshwater lake in the world and also the biggest lake i have ever seen (the largest in South America) in my life. You could easily mistake Lake Titicaca for a sea, standing on the shore it is a vast beautifully blue scene of water as far as the eye can see.