Pergamon

The theatre drops away at an angle that makes your stomach lurch — eighty rows of stone seats plunging down the hillside at a gradient steeper than any Roman architect would have dared. Wind whips across the acropolis, carrying the scent of wild thyme from the slopes below. From the top tier, the Aegean plain rolls out toward a haze that might be sea.

Pergamon, near modern Bergama in Turkey's İzmir province, was one of the great intellectual and cultural centres of the ancient Mediterranean. Its acropolis, reached by cable car or a winding road, holds the steepest theatre of the ancient world — a 10,000-seat structure carved into the hillside at a near-vertiginous angle. The city rivalled Alexandria in learning: its library held 200,000 volumes, and the word 'parchment' derives from Pergamon, where the writing material was supposedly perfected when Egypt cut off papyrus supplies. The Asklepion, a Roman-era healing centre in the lower town, was one of antiquity's most advanced medical facilities. The Great Altar of Pergamon, excavated in the 19th century, now resides in Berlin's Pergamon Museum — a source of ongoing restitution debate. The Red Basilica, a massive 2nd-century temple later converted to a church, is one of the Seven Churches of Revelation.