Reinhard Heydrich, the "Butcher of Prague" and architect of the Holocaust's organizational framework, was considered so dangerous that the Czechoslovak government-in-exile planned his assassination. In December 1941, Jozef Gabčík and Jan Kubiš were dropped by parachute into the Protectorate of Bohemia and Moravia.
On May 27, 1942, as Heydrich's open-top Mercedes slowed for a hairpin turn in Prague, Gabčík stepped into the road with a Sten gun—which jammed. Kubiš then threw a modified anti-tank grenade that detonated near the car, embedding shrapnel and horsehair from the upholstery into Heydrich's body. He died of septicemia on June 4.
The Nazi reprisals were devastating: the village of Lidice was completely destroyed, its men executed, women sent to Ravensbrück, and children either killed or given to German families. Gabčík and Kubiš, along with five other paratroopers, made their last stand in the crypt of the Church of Saints Cyril and Methodius in Prague, where they fought until their ammunition ran out.