▁all ▁the ▁functions ▁of ▁local ▁government ▁for ▁a ▁con urb ation . ▁This ▁is ▁by ▁contrast ▁to ▁areas ▁which ▁are ▁primarily ▁rural , ▁where ▁the ▁local ▁government ▁is ▁divided ▁into ▁district ▁municipal ities ▁( com par able ▁to ▁a ▁" count y " ▁in ▁the ▁US ) ▁and ▁local ▁municipal ities . ▁There ▁are ▁eight ▁metropol itan ▁municipal ities ▁in ▁South ▁Africa . ▁ ▁Mor oc co ▁ ▁In ▁Mor oc co ▁there ▁are ▁five ▁metropol itan ▁areas : C as ab lan ca , ▁Rab at , ▁Tang ier , ▁F es ▁and ▁Mar ra ke ch ▁are ▁considered ▁Mor oc co ' s ▁biggest ▁metropol ises . ▁Of ▁these , ▁Cas ab lan ca ▁is ▁the ▁largest . ▁ ▁Amer icas ▁ ▁Argentina ▁▁ ▁In ▁Argentina , ▁Buenos ▁Aires ▁is ▁the ▁principal ▁metropol is ▁with ▁a ▁population ▁of ▁around ▁fifteen ▁and ▁a ▁half ▁million . ▁The ▁Gre ater ▁Buenos ▁Aires ▁con urb ation , ▁which ▁also ▁includes ▁several ▁Buenos ▁Aires ▁Province ▁districts , ▁constit utes ▁the ▁third - larg est ▁con urb ation ▁in ▁Latin ▁America . ▁Buenos ▁Aires ▁is ▁the ▁main ▁political , ▁financial , ▁industrial , ▁commercial , ▁and ▁cultural ▁hub ▁of ▁Argentina . ▁ ▁Brazil ▁ ▁In ▁Brazil , ▁São ▁Paulo ▁is ▁the ▁principal ▁metropol is ▁with ▁over ▁ 2 0 ▁million ▁inhabitants . ▁In ▁the ▁larger ▁cities , ▁such ▁as ▁São ▁Paulo ▁and ▁Rio ▁de ▁Janeiro ▁( pop ulation ▁ 6 . 3   mill ion ), ▁fav el as ▁( sl ums ) ▁grew ▁up ▁over