Nice shot. That must be a ditch surrounding the fort. I love to see and learn about the architecture of fortresses and castle and how they are geared to withstand attacks by enemy.
The trench is inside the ramparts. If google (or wiki) Palmerston’s Follies, it’ll tell you about the range of forts built around Portsmouth in the 1850’s to defend against a possible French. Invasion which in reality was probably never likely. @sangwann@wakelys
