Kdo je zgradil Kitajski zid?

Če je Kitajska zgradila Veliki zid, zakaj so obrambn stran postavili obrnjeno proti sebi? Zdi se da veliki zid ni izgradila Kitajska, temveč Tartari v času njihove izgraditve.

If China built the Great Wall, why would they place the defensive side facing themselves? Seems the great wall was not built by China, but the Tartarians at the time of its construction.