I read an interesting NY Times article about WWII bombs remaining active in Germany. This left me with a lot of questions. For one what does it mean when it says the Germans buried active bombs and built over them? Were active bombs moved to unsafe locations? Even in the interest of speed it seems like a bad idea to build over bombs.
"The Allies carpeted industrial or urban areas, among them Cologne and Berlin, with thousands of tons of bombs during the final years of the war. Rather than safely dispose of them at the time, the Germans simply buried them in the rush to rebuild adequate housing after 1945."
My other question may be less historical but I'm wondering how these bombs still potent. Most machines from the 1940 have deteriorated by now, even with active upkeep, it seems surprising that a bomb that was dropped from thousands of feet in the air and buried would remain a danger.
Well for your first question,
What does it mean when it says the Germans buried active bombs and built over them?
When a bomb such as the one in that article didn't explode, it would typically be embedded a few feet or more in the ground, many times leaving a small crater with it half buried in the center. During recovery the Germans had two options, 1) Take the chance of defusing the bomb, unburying it, transporting it to a safer location and defusing/dismantling it or destroying it with a controlled explosion 2) burying it where it was and leaving it for future generations to worry about. Option two was the faster and easier solution at the time and being that there were THOUSANDS of these things and each bomb could take hours if not days to disarm, they simply had to go with the faster option or the people of Berlin would have been without housing for years. As long as they weren't moved at all, then there wasn't too much worry about them going off.
As for the current potency of the bombs, while the outside is very corroded the triggering mechanism and payload itself still may very well be fully functional. There are few actual moving parts in a bomb, the bomb has a firing pin that is supposed to be released when a piece celluloid is deteriorated by acetone. If this doesn't happen the bomb won't go off. But if the celluloid deteriorates over say, 70 years, then it could go off at any the slightest movement. There are private companies that specialize in the defusing of this sort of ordinance, and since 2000, 11 disposal specialists have died while trying to disarm these weapons. They're definitely no joke! Hope this helped ^_^