Undetonated WWII-era bombs?

What is it with WWII bombs and explosives? One was found in suburban Paris today, 3 days ago, there was another from BBC News and yet most of them are discovered this year. To prove this, I shall link you to this a href="http://news.google.ca/news/search?aq=f&pz=1&cf=all&ned=ca&hl=en&q=WWII+bomb" rel="nofollow"http://news.google.ca/news/search?aq=f&p…/a