In less than 24 hours, two undetonated bombs were found in the cities of Warsaw and Munich causing mass evacuations, which made us wonder just how common it is to find a 70-year-old, 3,000 lb. bomb in bustling European cities. 

"Hardly a week goes by in Germany without an unexploded bomb from World War II being found at a construction site or in another location," wrote Spiegel Online this morning, which seemed like an exaggeration. Spiegel was reporting on last night's evacuation of some 3,000 people after a 550 lb. bomb was found around 10 p.m. Monday night in Munich. "Monday's find resulted in a mass evacuation of apartments and office buildings in Munich's popular Schwabing district, only a short walk from the city's world-famous tourist attractions," writes Spiegel, adding that "City officials in Munich estimate that 2,500 unexploded bombs are still buried in the Bavarian capital."  You read right. 2,500 bombs in Munich, alone. 

On the heels of that evacuation came another from Warsaw, Poland. Again, 3,000 more people were evacuated, reports Reuters. "The 1.5-tonne World War Two mortar bomb was discovered by underground construction workers in Poland's capital and later safely removed by bomb disposal experts," according to Reuters' team, reporting that the bomb was from 1944. 

So, Spiegel sure doesn't sound like it was exaggerating, ut the fact that people are finding undetonated WWII bombs, just hanging out below the surface sometimes on a weekly basis, still came as a shock. For anyone that didn't grow up in occupied Europe (the area, not the time) here are some things to keep in mind along with the fact that these unexploded bombs are officially called "unexploded ordnances":

There Were a Ton of Bombs Dropped on Occupied Europe

Well, obviously in order to have undetonated bombs, they have to come from somewhere. In today's report about Munich, NBC News threw out this statistic: "During World War II, Allied forces dropped nearly 2 million tons of bombs on Germany and experts estimate that between 5 to 15 percent of the bombs did not explode."  There are 2,000 pounds in a ton and that makes for about 4,000,000,000 pounds of bomb. Spiegel bolsters this claim, stating that "Between 1940 and 1944, 2.7 million tons of bombs were dropped on Germany and occupied Europe by British and American bombers." Going high, that's about 600,000,000 pounds of material that remain undetonated. And, as WWII Equipment  (a site dedicated to the weapons of WWII) points out, bombs ranged from a tiny 4 lbs, to a whopping 22,000 lbs with some 2,000 lbs 4,000 lbs and 8,000 lbs peppered in between. We could be talking anywhere between 27,000-300,000+ undetonated bombs in all of occupied Europe depending on the size. And from today's reports, the two bombs found in Munich and Warsaw differed greatly in size.

Who's Finding the Bombs?

In Warsaw, the bomb was found underground, but Reuters notes that from time to time bombs are found on construction sites in the center of the city. Construction workers also found the bomb in Munich, reports NBC News, which would make sense: that new construction would require demolition and digging—the type of things you would need to do to find an unexploded bomb that was dropped some 70 years ago. Spiegel wrote last year the bombs end up in fishing nets, during road work, and even by farmers. On Belgian and French farms, the term "iron harvest" was coined to describe the annual "harvest" of exploded shells, unexploded ammunition and grenades, and whatnot from WWI. But as the Chronicle of Higher Education points out, cities like Rennes, France and the suburb of Boulogne-Billancourt had their own scares from unexploded bombs after WWI. 

And How Often Are They Found?

So this is where it gets crazy. Spiegel reported in 2011 that in Germany "thousands of bombs are found each year, 15 a day as a statistical average." 15. Per. Day. They add that 5,500 bombs in Germany have to be defused each year. Again because size varies on the bombs, no one really knows a good number to estimate other than raw weight. But to give you an idea of how commonplace finding these antique bombs is, check this out: "This year alone in Munich, there have been four major discoveries of unexploded bombs," reports Spiegel.  And just last week Nuremberg, about 100 miles away from Munich, had to defuse its own WWII bomb, reported The Sacramento Bee.

Of course the big question now is what happens to when you find these gigantic bombs. In Munich, it seems like they're still trying to figure out what to do with it.  Spiegel reports that officials and the fire department have covered the bomb with straw and sand so they can safely detonate it, while Warsaw's bomb team defused the dud, reports Reuters. And thankfully, in both cities, no one was hurt.

So, yep. Nothing to see here. Just your average, 70-year-old, half-ton bomb. Back to work. They'll probably find a few more tomorrow.