During World War II, the cathedral was seen as a symbol for both warring parties. Adolf Hitler, who visited it on 28 June 1940, intended to transform the church into a "national sanctuary of the German people", or into a monument to the Unknown German Soldier. On 1 March 1941, General Leclerc made the "Oath of Kufra" ("serment de Koufra"), stating he would "rest the weapons only when our beautiful colours fly again on Strasbourg's cathedral". During that same war, the stained glass was removed in 74 cases. and stored in a salt mine near Heilbronn, Germany. After the war, it was returned to the cathedral by the Monuments, Fine Arts and Archives section of the United States military.