The Istibei Fort of the Metaxas Line in Serres

The Istibei Fort is located at an altitude of 1,339 meters on Mount Kerkini, also known as Mpelles, approximately 16 kilometers from Neo Petritsi in the Serres region and about 250 meters from the Greek-Bulgarian border line. It was part of the fortification complex of the Metaxas Line in Macedonia. In 1941, its garrison consisted of 10 officers and 300 soldiers. The fort had 30 surface-level defensive structures and 2,297 meters of underground tunnels, forming a sealed and self-contained complex. Today, it operates as a museum. The fort and its personnel went down in history for their fierce resistance during World War II, when German troops invaded Greek territory on April 6, 1941. Initially, the Germans attacked the fort with artillery fire, followed by aerial bombardments. After the bombing ceased, German infantry forces advanced and even managed to penetrate the interior of the fort, but were repelled by the Greek defenders. By the morning of April 7, 1941, all surface-level defensive structures had been destroyed. Repeated attempts by the Germans to descend into the tunnels were met with strong resistance and heavy casualties. Eventually, the Germans managed to block the embrasures of the machine-gun nests and other fortifications and released suffocating gas into the tunnels, forcing the fort’s commander, Major Xanthos Pikoulakis, to order its surrender. During the two-day battle to defend the fort, 15 Greek soldiers were killed and 50 were wounded. German casualties were significantly higher. Pictured: Soldiers of the Istibei Fort garrison after the end of the battle that took place on April 6–7, 1941. ©Municipal Photography Museum of Kalamaria ‘Christos Kalemkeris’.