During the two world wars for strategic reasons the region each time became the passage for the invading armies because of the narrow width of the Meuse and its deep valley. The French military believed that the region was defended by its terrain and thick forests present in the northern of the department and so neglected the defence of the territory. During the First World War the Battle of the Ardennes was fought in the department and Charleville-Mézières became the headquarters of the German Crown Prince. It was at Vouziers and other places that the Czechoslovak legions fought , and it was also near the same city that the aeroplane of Roland Garros was shot down.