The historic city of Machu Picchu is located in the Cusco Region of modern day Peru. It sits atop a mountain overlooking the Urubamba Valley, which is situated 50 miles northwest of the city of the Cusco proper.
The river which flows through the valley hems Machu Picchu in on three sides, making a natural break in the landscape.
This location was chosen deliberately, as the city was a military secret, and it was built in such a way as to make it easily defensible.
Sitting a full 8,040 feet above sea level, the sheer cliffs which surround it provided excellent fortification.
Between Two Summits
Machu Picchu rests between the two summits of Huayna Picchu and Machu Picchu. It looks down into valleys on either side, and to its rear sits a peak which is nearly impossible to climb.
Again, archeologists believe this orientation was specifically chosen, to offer the maximum level of defense.