A World War II bomb was blown up Thursday in a controlled explosion in a rail yard in the German city of Leipzig after bomb experts ruled it was too dangerous to defuse, dpa reported. The 75-kilogram US bomb, dropped on the city in an Allied air raid, caused a massive explosion. About 300 residents had been evacuated from their homes and police diverted all traffic away from the scene, about 1 kilometre north of Leipzig's main railway station. Commuter rail services had been snarled by the discovery Wednesday evening during construction work.