1Citadel of Aleppo, Syria

Much of the current-day citadel dates back to the Ayyubid dynasty of the 12th and 13th centuries, but the 100-foot high limestone hilltop site has been historically significant since at least the middle of the third millennium BC.

Although the citadel came under heavy fire during the civil war — with government troops using it as a military base — and sustained significant damage, the striking structure still remains, its fortified entrance as imposing today as it was over 800 years ago.