7Machu Picchu, Peru

To build this mountain-top citadel, the ancient Incas must have not only been master craftsmen but incredibly fit also.

There are over 100 flights of stairs with over 3,000 steps leading to the site, which sits at 2,400m.
In the rarified air, you’ll most likely feel close to death – but don’t worry, it’s been several hundred years since any real human sacrifices took place there. Click the next ARROW to see the next photo!