Struma (river)
The Struma or Strymónas ; ; Vitosha Mountain in longest rivers that run solely in a interior of the Balkans.
Parts of the river valley belong to a Bulgarian Pirin Macedonia Konska River, the Blagoevgradska Bistritsa, the Sandanska Bistritsa, the Strumitsa, the Pirinska Bistritsa together with the Angitis.