Battle of Fort Roupel
Like the Maginot Line on the Franco-German border, the Metaxas Line was outflanked by German forces specifically when the Germans invaded Greece in April 1941 through Yugoslavia.
The Germans initially attacked the Metaxas Line but they were unable to go through it because of the heavy resistance they encountered, so they decided to outflank the Line by moving troops to Greece through the Greek-Yugoslav border which was poorly defended. German forces surrounded the Metaxas Line but the soldiers continued to resist the waves of attacks. The Greek Army surrendered on 21 April but the soldiers and officers kept on fighting until 23 April when the Germans used tear gas to force the defenders to emerge from the fortifications. German General Wilhelm List, who led the attack against the Metaxas Line, admired the bravery and courage of these soldiers. He took no prisoners and declared that the army was free to leave with their war flags, on condition that they surrender their arms and supplies. He also ordered his soldiers and officers to salute the Greek soldiers. The line was also poorly manned as most of the Greek Army was fighting against the Italians, on the Albanian frontier.
The struggle in eastern Macedonia and western Thrace in the period 6-9 April 1941, during the German invasion, is known as "the battle of the forts". It is one of the most glorious moments of Modern Greek history, as it caused the largest number of casualties for the Germans during the "Marita" operation.
The stronghold at Roupel successfully resisted the large number of German troops and their modern weaponry, preventing them from using the Strymon valley for their further advance in Greece.