Even when I was going to school in the late 80’s/early 90’s we’d often have the odd day off because of recently discovered unexploded bombs.
Shame they haven’t got round to filling in the holes yet, oh no whoops they’re the potholes Mr Rotherham……
Completed in 1911 I think. The tour you can go on is worth it.
The Old Dock Tour is free and is something I would actually willingly pay for. I highly recommend it.