Explanation: During WW2, British and American bomber command in Europe pursued different strategies for fighting the Nazis. The British employed a strategy of area bombing, or, less charitably, terror bombing, in which large swathes of German cities were indiscriminately flattened at night-time in the hope that this would sap the morale of the German population to continue fighting. Post-war studies would show that this was not the case, and one might think that the British, themselves, the subject of German terror bombing early in the war which only stiffened their resolve, might have cottoned on to that a little faster.
American bomber command preferred daylight raids in the hopes of destroying strategic military and industrial targets in order to sap the material ability of Nazi Germany to resist. This is generally agreed to have been more effective.
The two, however, converged on Dresden - a major transport hub for the German war machine, especially regarding transport of materiel to the Eastern Front. A joint British-American firebombing raid killed tens-of-thousands of civilians. While there was some military justification for the raid, it's generally agreed that the civilian damage was excessive and that the raid was one of the least justifiable decisions of the Western Allies of the war. It provided the Nazis with considerable propaganda material, and gets passed around even today with exaggerated numbers.
https://en.wikipedia.org/wiki/Bombing_of_Dresden
'Funny' enough, despite the Americans engaging in a more targeted bombing campaign in Europe, American firebombing in Japan was every bit as pointlessly brutal and murderous as the Brits were in Europe - if not worse, considering the extremely flammable nature of 1940s Japanese civilian structures.