On May 14, 1938, more than 100,000 soccer fans filed into Berlin’s Olympic Stadium to watch the English team trounce Germany. At this pre-World War II moment, the two countries were still making gestures toward diplomacy while eying each other warily. During the game, swastikas and British flags flew side by side in the packed stadium, while the German national anthem blared over the loudspeakers. Then, on the field below, the German — and the British — players raised their arms in the Nazi salute.

The British press was shocked. What were British soccer players doing making a fascist gesture? Turns out the salute had been ordered in advance by the British Foreign Office as part of Prime Minister Neville Chamberlain’s plan to avoid conflict by appeasing Hitler. The bizarre gesture of diplomacy and the broader policy of appeasement toward Hitler was, of course, a mistake. Just over a year later, Germany would invade Poland, prompting the British and French to declare war. The wheels of war were already in motion on the day of the soccer match, but it’s only natural to see the image of British players heiling Hitler as a warning about what can happen if you give a Nazi an inch: they try to take the world.