There is supposed to a be sunken WW2 American amunition ship lying in the Thames estuary. Because of the dangerous state of the cargo no attempt has been made to recover the ship or contents. Ships just have to sail round it. I have only found one passing reference to this ship on Google but I think that it is a true story. It is estimated that if this ship ever explodes it will take out most windows in Southend on Sea and probably wreck some buildings.Mind you it couldn’t happen to a nicer place. 
That would cause POUNDS worth of damage!
I remember being told (by a bloke in a pub - the best source there is) that if Canvey Island ever blew up it would be not dissimilar to a nuke going off. This could of course be total 'nads.
Not exactly Berlin, but I used to work in a part of Hamburg that was targeted heavily during “Operation Gomorra” (says it all, doesn’t it ?) - near the docks.
The area was undergoing a lot of construction - the 1950s somewhat quick-and-dirty postwar construction being replaced by modern office buildings. Lots of foundations going deeper than those of the previous buildings… Finding WWII ordnance was enough of a routine event that it hardly merited a news story, except if it was an exceptional heavy bomb or if the evacuation blocked traffic for longer than usual.
The UXO disposal crews, charmingly known as the “Himmelfahrtskommando” - lit., “Ascension Command” (as in, one mistake and you’re sky- as well as heaven-bound) are extremely competent, though. But even so, on average two WWII pieces of ordnance per year detonate within the city limits.
A bit of a sideways leap here:-
I have read that the Tirpitz which is sjunk in a fjord in Njorway, is now a threat as it is leaking oil. Now if a pocket battleship were to blow up…
Tirpitz was cut up for scrap after it was sunk in shallow waters.
You’re probarbly thinking about the heavy cruiser Blücher which was sunk in the Oslofjord. I think an amunition ship had much more explosives aboard then a battleship so the explosion would be smaller.
Another big bang waiting to happen is located on the French/ Belgium border , near the town of Ypres. This is one of a series of underground tunnels which were dug under German lines and packed with explosives , to be detonated at the start of a battle. Two of these ‘mines’ were not set off and the records about them were lost. In 1955 , after the ground was struck by lightning , one exploded but there is another one out there waiting to go off. If you are thinking of buying land in that area , be very careful !.
This link gives more details :-
http://www.diggerhistory.info/pages-battles/ww1/france/messines.htm
I’ve heard of this. I’m trying to get the name of the ship at the moment - it has involved several phone calls, including a transatlantic call, so far.
I live in Southend-on-Sea, within 100 yards of the seafront. Even so I have to agree that a bomb blast could only improve the place 
Wow. You’re not talking about the SS Richard Montgomery, are you?
I found a picture of it about halfway down this page. There are numerous other articles out there. One states that the munitions were stored on one deck of the ship and the explosives were stored beneath them. When a storm caused the ship to break apart, the detonators fell amongst the munitions, making it too dangerous to continue the recovery.
There’s a significant difference between this shipwreck and UXBs you find in cities which were the target of aerial bombardment. UXBs are presumed to be armed munitions, with detonators, while the Montomery’s cargo was not primed for combat use. That makes the probability of an explosion somewhat smaller for the Montgomery, but it is still a non-zero probability.
My bad. The detonators were kept on one deck, and the munitions were stowed beneath.
That’s the one! Thanks, Sofa King.
Looks at location: Playground of the Damned… Hey, you aren’t from Southend too, are you?