▁area ▁of ▁DE 7 1 3 6 3 0 1 , ▁Wel ten burg ▁N arrow s ▁and ▁Hir sch berg ▁and ▁Alt m ühl le iten . ▁ ▁In ▁addition , ▁the ▁area ▁is ▁also ▁ge ot ope ▁no . ▁ 2 7 3 R 0 0 5 . ▁In ▁ 2 0 0 2 ▁the ▁Wel ten burg ▁N arrow s ▁was ▁awarded ▁an ▁official ▁se al ▁by ▁the ▁Bav arian ▁Minister ▁for ▁the ▁Environment ▁for ▁being ▁one ▁of ▁Bav aria ' s ▁most ▁beautiful ▁ge ot op es . ▁In ▁ 2 0 0 6 ▁The ▁Dan ube ▁G orge ▁was ▁listed ▁among ▁the ▁ 7 7 ▁out standing ▁national ▁ge ot op es ▁of ▁Germany . ▁ ▁Ge olog ically ▁the ▁Wel ten burg ▁N arrow s ▁belong ▁to ▁the ▁Upper ▁Jur ass ic ▁( lim estone ), ▁and ▁therefore ▁the ▁most ▁foss il - rich ▁form ations ▁in ▁Germany , ▁which ▁was ▁laid ▁down ▁about ▁ 1 5 0 ▁million ▁years ▁ago ▁when ▁the ▁area ▁was ▁still ▁a ▁shall ow ▁sea . ▁ ▁The ▁g orge ▁is ▁en closed ▁on ▁either ▁side ▁by ▁rock ▁faces ▁up ▁to ▁ 8 0   met res ▁high , ▁pier ced ▁by ▁numerous ▁small ▁c aves . ▁Between ▁the ▁so - called ▁Still en ▁and ▁the ▁rocks ▁of ▁the ▁L ange ▁W and ▁( Long ▁Wall ) ▁the ▁river ▁narrow s ▁by ▁up ▁to ▁ 1 1 0 ▁metres ▁and ▁att ains ▁a ▁depth ▁of ▁ 2 0   met res .