In May 1942, two Czechoslovak paratroopers sent by the government in exile in London carried out the assassination of Reinhard Heydrich, the Bohemian puppet state's Nazi overseer.
The paratroopers, along with several partisans who assisted in the plot, fled to the crypt of the Orthodox Cathedral of Ss. Cyril and Methodus.
Another partisan however betrayed them to the Germans, who tried first of all to shoot their way into the crypt, then to flush the men out with water.
Sadly, on realising there was no escape, the resistance fighters committed suicide.
The dramatic story is retold in the crypt of the church where the events took place, entitled the National Memorial to the Heroes of the Heydrich Terror.
Photos from the period and explanations recount an event which is heroic, sad, and at the same time, frustrating.
The Heydrich assassination led to hundreds of innocent people, including almost the entire village of Lidice, paying with their lives.
The museum also tells the wider story of Czech people who resisted Nazi occupation.