WARSAW, Poland (AP) — A group of 50 British air force officers set off Tuesday to march from the site of a Nazi prisoner camp to a war cemetery in western Poland to mark 70 years since the Great Escape of Allied airmen and to honor 50 of them who were caught and executed.

Marek Lazarz, director of the Stalag Luft III Museum, told The Associated Press that the group started in pouring rain from a monument marking the place where 76 prisoners of war emerged, one by one, from a tunnel on March 24 and 25, 1944. The 77th man was spotted by guards, who gave chase. The 1963 Hollywood movie “The Great Escape,” starring Steve McQueen, tells the story.