Termessos

Writers in antiquity referred to Termessos as the Eagle's Nest, and when you visit the 4,500-foot-high site, you'll understand why. Seemingly impregnable, Termessos remained autonomous for much of its history and was quite wealthy by the 2nd century AD. Most of the ruins date from that period. A visit takes at least four hours, and there is no restaurant on-site, so pack water and lunch, and wear sturdy shoes.