Fort Frederick is the oldest British structure in South Africa still standing in its original form — a small stone fort built in 1799 on the hill above the Baakens River, about three years before the first permanent settlement at what would become Port Elizabeth. It was built in a hurry during the brief first British occupation of the Cape Colony, to guard the anchorage against a possible French naval attack in the Napoleonic Wars. The attack never came.
The fort is compact — four walls, four bastions, a couple of rooms inside — but it has a dignity that larger ruins often lack. It sits in a small park with good views over the harbour entrance, and admission is free. Most visitors combine it with a walk up to the Donkin Reserve, which is five minutes away on foot uphill. The interior has some interpretive panels about the 1820 Settlers and the early colonial history of the Eastern Cape.