Fujian Tulou (earth structure) from back in 1200 before they were famous for knockoffs.
http://en.wikipedia.org/wiki/Fujian_Tulou
Apartment complex villages build on top of mountains, strong as a castle with flame resistant iron plated 13cm thick wooden gates, granite gate frame, and cobble wall. Gun ports on the top floor, circular corridors for troops and ammunition movements. It is also immune to cannon fires and bandits resistant.
http://en.wikipedia.org/wiki/Fujian_Tulou
Apartment complex villages build on top of mountains, strong as a castle with flame resistant iron plated 13cm thick wooden gates, granite gate frame, and cobble wall. Gun ports on the top floor, circular corridors for troops and ammunition movements. It is also immune to cannon fires and bandits resistant.





