This Orthodox church was built in honour of Sts. Cyril and Methodius, the men responsible for the Slavonic alphabet. However, most people know about this church because of what happened here at 04:10 on the morning of June 18, 1942 when the Nazis had discovered that the seven Czech parachutists involved in the assassination of Reichsprotektor Heydrich were hiding in the crypt. The west side of Karlovo náměstí was cordoned off by 800 troops from the SS and the Gestapo. Three of the soldiers died as the SS stormed the church. The remaining four fought on. After hours of shooting and a long stand-off which led to the Germans deciding to literally flush them out, they used their last bullets on each other. The bullet-scarred exterior wall holds a plaque in honour of their bravery.

A permanent exhibition to the memory of those who participated in the assassination of Reinhard Heydrich in 1942 is here. The small, but very in depth display maps the Czechoslovak resistance movement against the Nazis and includes photographs and memorabilia from the time. There are also films showing on TV screens and backgrounds into the seven paratroopers who participated in the mission.