2NB5 Smederevo Fortress Explosion Souvenir Sheet

VF NH, Sept. 1941, souvenir sheet with surcharge to collect funds for victims of June 5, 1941 ammunition explosion in the historic Smederevo fortress. The explosion killed 2,500 and wounded another 5,500 in the town and destroyed much of the fortress. Showing the Smederevo fortress, which dates back to 1427, and refugees. Same stamp designs as regular issue with different colors and much higher surcharge.