This was no terror incident, though. The 200-pound (91-kilo), 3-foot-long (1-meter-long) bomb was nearly 70 years old, dropped by a Soviet plane during the Second World War. Once its detonator was carefully removed, the TNT-packed iron tube was strapped to the bed of a truck and moved to a forest outside the city, where it could be safely detonated.

For most Berliners, the episode was more inconvenient than incredible. World War II bombs are part of life here, regularly turning up during construction projects and even in open fields and riverbeds. Dozens are discovered and defused each year.

Only the biggest make the news: In November 2011, the city of Koblenz evacuated 45,000 people—half its population, including two hospitals, seven retirement