Upnor Castle in Medway

You're standing at Upnor Castle, an artillery fort on the west bank of the River Medway in Kent. Across the water, a little upstream, was once Chatham Dockyard. This fort was built to guard that dockyard and the warships of the Royal Navy anchored in the river. Elizabeth the First had it built between 1559 and 1567, at a time of rising tension with Spain.