Birnin Ƙarƙashin ƙasa tsari ne na ma'ajiyar bama -bamai na lokacin Yakin Cacar Baki wanda ya ƙunshi hanyar sadarwa na ramuka da ke ƙarƙashin birnin Beijing, China . An kuma kira ta a matsayin Babban Bango na Ƙasa tun lokacin da aka gina ta don manufar tsaron sojoji . An gina katafaren gidan daga shekarun 1969 zuwa 1979 a cikin tsammanin yakin nukiliya tare da Tarayyar Soviet, yayin da dangantakar Sino-Soviet ta tabarbare kuma an sake bude shi a hukumance a 2000. An ba wa baƙi damar zagaya sassan ginin, wanda aka bayyana shi da "duhu, danshi, kuma da gaske". An rufe birnin ƙarƙashin ƙasa don gyarawa tun a kalla watan Fabrairun 2008. Hanyoyin ƙarƙashin ƙasa na ƙarƙashin ƙasa suna gudana a ƙarƙashin tsakiyar birnin Beijing, suna rufe 85 square kilometres (33 sq mi) 8 to 18 metres (26–59 ft) a ƙarƙashin farfajiya. A wani lokaci akwai ƙofofi kusan 90 na ginin, duk an ɓoye su a shagunan da ke kan manyan titunan Qianmen . Da yawa daga cikin hanyoyin shiga an rushe su ko an toshe su don sake gina su.