Dora I
Dora I ( Dora 1 ) is a former German submarine base and submarine pen or bunker built in Trondheim , Norway . 
<triplet> Dora I <subj> submarine base <obj> instance of <triplet> submarine pen <subj> submarine base <obj> subclass of <subj> bunker <obj> subclass of <triplet> Trondheim <subj> Norway <obj> country