World War II: Operation Gomorrah: The Royal Air Force bombs Hamburg, Germany causing a firestorm that kills 42,000 German civilians.

The Allied bombing of Hamburg during World War II included numerous attacks on civilians and civic infrastructure. As a large city and industrial centre, Hamburg's shipyards, U-boat pens, and the Hamburg-Harburg area oil refineries were attacked throughout the war.

Hamburg, officially the Free and Hanseatic City of Hamburg, is the second-largest city in Germany after Berlin and 7th-largest in the European Union with a population of over 1.9 million. The Hamburg Metropolitan Region has a population of over 5.1 million and is the eighth-largest metropolitan region by GDP in the European Union.

A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used to describe certain large fires, the phenomenon's determining characteristic is a fire with its own storm-force winds from every point of the compass towards the storm's center, where the air is heated and then ascends.