I love empty run down seaside places, and my hometown of Southend has some good ones.
Recently I had to spend some time there to help look after my mum. I got about an hour or so every day to go for a run. One route I kept repeating is straight down to the seafront and along to Shoebury Garrison. Shoebury has that end of the line vibe (no offense), partly because it actually is at the end of the Fenchurch St train line, and partly because the views over the Thames Estuary there are especially grim, which, as I said before, I love.
When I was a kid Shoebury Garrison was an army base and experimental artillery range. Nowadays it comprises chic converted residential housing, and the artillery range is a reclaimed-by-nature wildlife area, with old army piers and gun emplacement buildings still standing.
The same old empty seaside barren feeling and huge skies are still its main feature though. When the tide is out, which seems to be most of the time, large expanses of mud stretch away into the distance. Everywhere signs warn you not to wander around in case things blow up and kill you.