Dominating the skyline of 1200-year-old Hamburg, Germany, stands the towering ruins of St. Nikolai Church. At the time of its reconstruction in 1874, it was the world’s tallest building. Today it is a blackened skeleton of its former glory and a haunting reminder of one of the most devastating bombing campaigns of World War II. In July 1943, the Allied Combined Bomber Offensive launched Operation Gomorrah, a multi-day campaign that culminated in some of the war’s most devastating firebombing.