Apollonia is the ancient harbour of Cyrene, spread along the Mediterranean beside the modern town of Susa. It is one of the great places of Greek and Byzantine Cyrenaica: lower-key than Leptis Magna, less famous than Cyrene, but wonderfully placed where ruined walls and churches meet a pale, rocky coast.
The city began as Cyrene's port and later became one of the five cities of the Libyan Pentapolis. Earthquakes and coastal change have partly drowned the old harbour, so Apollonia has an unusual split personality: some ruins stand on land, while other blocks and harbour works lie under shallow water offshore.
The best circuit takes in the theatre, the west basilica, the eastern basilica, the city wall and west gate, and the small Apollonia Museum. If you have a guide and enough time, add Haua Fteah, a major prehistoric cave a short drive east.
Apollonia is best treated as part of a wider Jebel Akhdar trip with Cyrene, Qasr Libya and Derna. Security rules in eastern Libya can change quickly, and archaeological sites may require permissions, escorts or local introductions.