onne f ▁and ▁König sw inter ▁on ▁the ▁lower ▁part . ▁ ▁Trib ut aries ▁ ▁Lar ger ▁trib ut aries ▁on ▁the ▁left ▁include ▁Na he , ▁Mos elle ▁and ▁A hr ; ▁on ▁the ▁right ▁L ahn , ▁W ied ▁and ▁Sieg . ▁ ▁Cast les , ▁for tr esses ▁and ▁pal aces ▁▁ ▁The ▁most ▁out standing ▁cast les ▁are ▁the ▁Mark s burg , ▁the ▁only ▁und am aged ▁hill top ▁castle ▁in ▁the ▁Middle ▁Rh ine ▁Valley , ▁the ▁Burg ▁Pf al z g raf en stein , ▁on ▁a ▁rock y ▁island ▁in ▁the ▁middle ▁of ▁the ▁Rh ine , ▁and ▁R he inf els ▁Castle , ▁which ▁was ▁developed ▁into ▁a ▁for tr ess ▁over ▁time . ▁St ol zen f els ▁Castle ▁is ▁a ▁syn onym ▁for ▁Rh ine ▁rom antic ism ▁like ▁no ▁other . ▁It ▁did ▁not ▁just ▁encou rage ▁the ▁accept ance ▁of ▁the ▁existing ▁cast les , ▁it ▁also ▁encourag ed ▁their ▁rest oration ▁and ▁the ▁building ▁of ▁even ▁more ▁cast les . ▁The ▁Elect oral ▁Palace ▁in ▁Kob len z ▁was ▁the ▁last ▁residence ▁of ▁the ▁Elect ors ▁of ▁T rier . ▁ ▁It ▁was ▁demol ished ▁by ▁the ▁French ▁revolution ary ▁army . ▁The ▁most ▁powerful ▁for tr ess ▁in ▁Rh in eland - Pal at inate , ▁Kob len z ▁Fort ress , ▁was ▁built ▁in ▁the ▁ 1 9 th ▁century ▁by ▁the ▁Pr us si ans . ▁Ehren bre it stein ▁Fort ress , ▁once ▁part