belfort ruins or belfort castle (burg belfort oder burgruine belfort) over the river albula or alvra, surava

albula alvra ancient architecture attraction autumn belfort blue building burg burgruine canton castle clouds construction europe european exterior forest fortress graubuenden graubünden green grisons hill historic historical history kanton landmark landscape medieval mountain mountains nature oder old outdoor river rock romantic ruin ruins scene scenery scenic schweiz sky stone summer surava swiss switzerland tourism tower travel tree trees trip valley view village wall wanderlust