▁( then ) ▁modern ▁urban ▁development ▁plans . ▁Because ▁the ▁ground ▁was ▁mar sh y ▁and ▁too ▁low ▁to ▁be ▁protected ▁from ▁Rh ine ▁flo ods , ▁all ▁the ▁new ▁houses ▁were ▁built ▁on ▁raised ▁ground , ▁sometimes ▁as ▁high ▁as ▁ 5 ▁metres ▁above ▁the ▁original ▁ground . ▁Vis itors ▁can ▁see ▁the ▁original ▁ground ▁level ▁in ▁many ▁back y ards ▁of ▁Ludwig sh afen , ▁which ▁are ▁sometimes ▁two ▁flo ors ▁below ▁street ▁level . ▁ ▁World ▁War ▁I ▁through ▁World ▁War ▁II ▁During ▁World ▁War ▁I ▁( 1 9 1 4 - 1 9 1 8 ), ▁Ludwig sh afen ' s ▁industrial ▁plants ▁played ▁a ▁key ▁role ▁in ▁Germany ' s ▁war ▁economy , ▁producing ▁chemical ▁ing red ients ▁for ▁m un itions , ▁as ▁well ▁as ▁much ▁of ▁the ▁poison ▁gas ▁used ▁on ▁the ▁Western ▁Front . ▁This ▁contributed ▁to ▁Ludwig sh afen ▁having ▁the ▁dub ious ▁honour , ▁on ▁May ▁ 2 7 , ▁ 1 9 1 5 , ▁of ▁being ▁the ▁target ▁of ▁the ▁world ' s ▁first ▁strateg ic ▁aer ial ▁bomb ard ment . ▁French ▁aircraft ▁attacked ▁the ▁B AS F ▁plants , ▁killing ▁twelve ▁people ▁and ▁setting ▁the ▁preced ent ▁for ▁the ▁age ▁to ▁come . ▁ ▁When ▁the ▁war ▁was ▁lost ▁by ▁Germany ▁in ▁ 1 9 1 8 , ▁the ▁left ▁bank ▁of ▁the ▁Rh ine ▁was ▁occupied ▁by ▁French ▁troops , ▁in ▁accord ance ▁with ▁the ▁terms ▁of ▁the ▁peace ▁agreement . ▁The ▁French ▁occupation ▁last ed ▁until ▁