▁built ▁according ▁to ▁the ▁fort ification ▁system ▁developed ▁by ▁Lieutenant ▁Colonel ▁Raymond ▁Ad ol phe ▁S éré ▁de ▁R ivi ères . ▁The ▁goal ▁was ▁to ▁build ▁a ▁dis continu ous ▁en closure ▁around ▁Met z ▁using ▁a ▁series ▁of ▁art illery ▁for ts ▁spac ed ▁a ▁can n ons hot ▁apart . ▁In ▁the ▁ 1 8 6 0 s ▁t ension ▁was ▁rising ▁between ▁France ▁and ▁Germany , ▁causing ▁France ▁to ▁attend ▁to ▁the ▁fort ification ▁of ▁its ▁front iers . ▁Met z , ▁close ▁to ▁the ▁border ▁and ▁a ▁strateg ic ▁road ▁and ▁rail ▁crossing , ▁was ▁the ▁benef ici ary ▁of ▁one ▁of ▁the ▁first ▁programs ▁of ▁fort ification . ▁Before ▁all ▁of ▁the ▁for ts ▁could ▁be ▁completed , ▁France ▁was ▁defeated ▁in ▁the ▁Franco - Pr uss ian ▁War ▁and ▁the ▁area ▁around ▁Met z ▁was ▁an nex ed ▁to ▁Germany . ▁Met z ▁then ▁became ▁a ▁cru cial ▁strong point ▁on ▁Germany ' s ▁front ier , ▁receiving ▁sust ained ▁attention ▁to ▁its ▁def enses ▁that ▁cul min ated ▁in ▁the ▁Mos el stellung ▁of ▁the ▁early ▁tw enti eth ▁century . ▁ ▁The ▁pre - war ▁French ▁construction ▁program ▁compr ised ▁eight ▁for ts ▁surrounding ▁Met z ▁at ▁a ▁distance ▁of ▁ 3 . 5 ▁- ▁ 5 . 5   km ▁from ▁the ▁center ▁of ▁the ▁city . ▁Pl anning ▁began ▁in ▁ 1 8 6 4 , ▁and ▁in ▁ 1 8 6 7 ▁the ▁project ▁was ▁placed ▁under ▁the ▁super vision ▁of