1. The Knights' Halls (Hospitaller Fortress) — Old City, north side
The vaulted Crusader city, excavated from beneath the Ottoman one.
The Knights' Halls are the excavated Crusader compound of the Hospitaller order — a complex of vast vaulted halls, a refectory, a courtyard and living quarters, buried for centuries beneath the Ottoman city built on top of it.
The scale is what surprises people: these are enormous Gothic spaces, largely intact, sitting a few metres below the streets you walked in on. The Crusader capital of the kingdom of Jerusalem in its final decades is essentially preserved under the modern town.
It is the single best reason to come to Akko, and it is where any visit should start.
Good to know: Buy the combination ticket at the entrance — it covers the tunnel and the hammam too and saves money.