als ▁Ma ▁Hong k ui ▁and ▁Ma ▁B uf ang ▁protected ▁L anz hou ▁with ▁their ▁caval ry ▁troops , ▁putting ▁up ▁such ▁resistance ▁that ▁the ▁Japanese ▁never ▁captured ▁L anz hou . ▁ ▁The ▁city ▁is ▁the ▁seat ▁of ▁a ▁currently ▁vac ant ▁Roman ▁Catholic ▁dioc ese ▁and ▁was ▁previously ▁the ▁center ▁of ▁a ▁vic ari ate ▁apost ol ic ▁( V ic ari ate ▁Apost ol ic ▁of ▁Northern ▁Kan - Su ). ▁ ▁Geography ▁ ▁Area : ▁ ▁E lev ation : ▁ ▁above ▁sea ▁level ▁China ' s ▁north west ▁ge ographical ▁center ▁More ▁than ▁ ▁of ▁urban isation ▁along ▁the ▁southern ▁banks ▁of ▁the ▁Y ellow ▁River . ▁Z on ary ▁bas in ▁Mountains ▁are ▁located ▁on ▁the ▁south ▁and ▁north ▁sides ▁of ▁the ▁city : ▁Q ilian ▁R anges , ▁M t . ▁P ing li ang ▁and ▁M t . ▁Kong t ong ▁( the ▁most ▁noted ▁in ▁T ao ism ) ▁River : ▁The ▁Y ellow ▁River ▁flows ▁through ▁from ▁west ▁to ▁east . ▁ ▁L anz hou ▁is ▁situated ▁on ▁the ▁upper ▁reaches ▁of ▁the ▁Y ellow ▁River ▁where ▁it ▁emer ges ▁from ▁the ▁mountains ▁and ▁has ▁been ▁a ▁center ▁since ▁early ▁times , ▁being ▁at ▁the ▁southern ▁end ▁of ▁the ▁route ▁leading ▁via ▁the ▁H ex i ▁Cor rid or ▁across ▁Central ▁Asia . ▁It ▁commands ▁the ▁approaches ▁to ▁the ▁ancient ▁capital ▁area ▁of ▁Ch ang ' an ▁( mod ern ▁X i ' an ) ▁in ▁Sh a an xi ▁province ▁from