Thousands of people have had to evacuate because of unexploded British bombs in Italy.
This is a lingering after-effect of the vast amount of ordnance used during the second world war. However, this isn’t the only country that has this problem, nor is WWII the only war that cause this sort of thing. Tons of explosives (some including toxic gasses, such as phosgene and mustard gas) have been found, and handling them has caused evacuations elsewhere. This is quite a worrisome problem, but very little can be done about it due to the massive number of devices involved.