The eroded remains of the river side brick bastion of Cockham Wood Fort, located about 500 metres west of Hoo Marina Park and Hoo Ness Yacht Club, Kent.
Built in 1669. “In conjunction with Fort Gillingham it took on the role of defending Chatham Dockyard from seaborne attack” (wikipedia).
There are more remains of the fort in the woods above this bastion.
633 photos taken with a Sony a7R III and 259 with a DJI Mini 2 in November 2023 and processed in Agisoft Metashape.