rumelian castle and roumeli hissar castle or bogazkesen castle, a medieval fortress located in istanbul, turkey, on a series of

ancient architectural architecture asia attraction blue bosphorus bosporus building castle citadel city cityscape coastline constantinople defense europe european exterior fort fortification fortress green heritage hills hissar historic historical history istanbul landmark medieval old ottoman park protection roumeli rumelian rumelihisari sea shore strait structure tourism tourist touristic tower travel turkey turkish wall