The Struma and Nestos rivers cut across the mountain range along the Greek-Bulgarian frontier and both of their valleys were protected by strong fortifications, as part of the larger Metaxas Line.
Strimon og Nestos-floden gennemskar bjergkæden langs den græsk-bulgarske grænse og begge deres dale var beskyttet af store befæstninger, som led i den mere omfattende Metaxas-linje.