The last opposed seaborne invasion of England happened here

In 1667, a Dutch fleet sailed up the Orwell and tried to take this fort. They failed. It was also, as it turned out, the first land battle ever fought by the Royal Marines.

That's not context. That's the reason Landguard Fort exists.

The fort has been here, in some form, for over 400 years - watching the mouth of the Orwell, guarding the approach to Harwich Harbour. It started as earthworks. Then stone. Then gun emplacements for two World Wars. And somewhere in the middle of all that, a Cold War control room was added to a stru…