Ms Merkel thanked the German officer, Claus von Stauffenberg, and other plotters who tried in 1944 to kill the Nazi dictator with a briefcase bomb.
Stauffenberg and some 200 co-conspirators were caught and executed.
Mrs Merkel urged people to join programmes for strengthening democracy.
"This day is a reminder to us, not only of those who acted on July 20, but also of everyone who stood up against Nazi rule," she said in her weekly video podcast.
"We are likewise obliged today to oppose all tendencies that seek to destroy democracy. That includes right-wing extremism." » | BBC | Saturday, July 20, 2019
