The Maritsa or Evros (Марица, Ἕβρος (Latinised as Hebrus), Έβρος, Evros, Meriç) is, with a length of 480 km, the longest river that runs solely in the interior of the Balkans. It has its origin in the Rila Mountains in Western Bulgaria, flowing southeast between the Balkan and Rhodope Mountains, past Plovdiv and Parvomay (where t...