Portsmouth

Two thousand years rise and fall with the tide as it swirls through the narrow channel at Portsmouth Point and into the harbour. The city is sited at, and named after, the mouth of a port, Portchester, around four miles further north. The great harbour is roughly shaped like a balloon: Portchester sits on top of it, Portsmouth is at its narrow mouth. Portchester has Roman origins, from around the first century ad, though the castle, which still survives, is of late third-century origins, part of the ‘Saxon Shore’ defensive system.