The Rupel fortifications are not far from the Serres-Promachonas national road, which leads to the Greek-Bulgarian border. They are just a short distance from the border in the narrow Rupel Gorge, through which the Strymon River flows. This place is of strategic importance for entry to Greek or Bulgarian territory and was fortified in 1914. File:Macedonian_Museums-95-Ohiro_Roupel-434.jpg|Model of a sergeant File:Macedonian_Museums-95-Ohiro_Roupel-435.jpg|Entrance of visitable tunnel File:Macedonian_Museums-95-Ohiro_Roupel-436.jpg|Map of the battle for the fort in April 1941