An unexploded aerial bomb from World War II retrieved from the Rhine River in Germany’s Cologne on Wednesday evening was safely defused overnight on a ship positioned away from residential areas, city officials said. Discovery of unexploded bombs is common in Cologne and other German cities, which were heavily bombed by Allied air forces during the war. Specially trained crews are dispatched to defuse or safely detonate the bombs. The British-made 5-tonne bomb had a rear-mounted fuse that was defused on board the ship, according to the Cologne city administration. The city said that there had …