At the beginning of WWII, the panels of the altarpiece of the Mystic Lamb were transferred to the French city of Pau. After 9 travel days they arrived there on May 26, 1940.
On August 3, 1942, the Germans robbed the panels and brought them over to the Bavarian Neuschwanstein Castle, from where they were transferred to the Salt Mine Altaussee in Austria, in 1944.
In this photo, we see Monuments Man Daniel J. Kern and art restorer Karl Sieber standing in the Altaussee mine after the masterpieces' rescue.