Bairro Alto was born with all the spices coming with Naus to Lisbon.
In-Game all cities can get Bairro Alto now, it replaces neighborhood but only one can be built. But like the real Bairro alto advantages gaining great people of culture.
Can only be built on hills like the actual Bairro alto, since the labor people were pushed to the hills where rich people got near the harbor plane area.
While rich harbor areas always changing culture, Bairro alto maintained the old one. Also with the Marchas Populares project which is happening in Portugal Nowadays.
Support: Portugal DLC needed.