German Dienstpost cover with Scott Nos. N17-N26 cancelled in Luxemburg on 20 December 1940.
* * *
At early dawn on 10 May 1940 the Germans struck all along the western front from the North Sea to Luxembourg. One spearhead drove along the Frisian coast, another thrust at the Yssel towards Utrecht, a third smashed at Maastricht and the fortress of Eben Emael commanding the Albert Canal, a fourth—the major attack—rolled through the rugged Ardennes towards the Meuse. Planes, bombed helpless cities, parachutists seized airfields and bridges, fifth columnists spread confusion and terror behind the lines.
From The History of the Second World War Edited by Henry Steele Commager