We had one explode in someone's back yard here in Vienna (Austria) a couple of weeks ago, it felt like an earthquake to people within a certain area. Luckily, no one was hurt, it just left a huge crater. They also come across them frequently when doing construction work for roads - you hear it on the radio that the motorway is closed until the bomb squad arrives. Scary stuff.
The Belgians have the same problem with a lot of the shells from the first war lying in the forests - only most of them are actually gas shells, slowly rusting.
Yup. DOVO, the Belgian army's demining service, still retrieves about 200 tons (i.e. 200,000 kg) of shells just from the small area in the northwest of the country where fighting was the heaviest. Accidents happen sometimes with farmers who dig up fosfor- or yperite - here's a picture of someone's hand 24h after touching some yperite (it's not pretty!): http://www.forumeerstewereldoorlog.nl/viewtopic.php?t=2325&#... . The caption says he used a handkerchief to wipe off his hand, which then also burnt his leg.
