I can help with your castles problem.
We dont have such castles in Bulgaria because during the Turkish "whatever" (when some nations were building their castles) we were not allowed to build tall buildings - including houses and churches. We were also not allowed to paint our homes in bright colours and to wear bright colours. This only made us create miracles - you will be surprised how many churches are built half-underground but in a way that they are not dark inside and they dont have mold. Ever. For example the world famous church in Dobarsko (it`s a branch of the National Historical museum) is made of stone but is positioned so precisely that the temperature inside remains the same during all seasons and the icons are perfectly preserved (if you have heard about the Jesus on a rocket).
If you want to see beauty in Bulgaria, a camera will not help, you need to look deeper.