This is a bit of a worry: https://en.wikipedia.org/wiki/SS_Richard_Montgomery

I suggest you don't buy property or go swimming nearby to that. I'm going to stick in Somerset.

Unexploded ordnance refers to ordnance that was deployed but failed to explode. E.g. the bomb was dropped from a plane and just didn't explode.

Deployed mines that haven't exploded are just waiting for someone to interact with them. This seems like it must be the highest risk.

This article appears to be about a cache of unused bombs. They would not ordinarily explode on their own, but if everything is decaying then the safety mechanisms are also decaying so there must be some risk.

There was a case in Virginia where a man was killed by a US civil-war era artillery round in his garage. Granted, he was in the process of making it safe at the time, but this was ~2010 from memory - so ~150 years after the conflict occurred.

Given that, we can obviously expect that some ordnance from WW2 will still be dangerous in 2095.

https://en.wikipedia.org/wiki/SS_Richard_Montgomery