Do Wonders like Coloseum and Pyramid of the Sun lose their effects upon age transition or do they just work on Quarters with Modern Buildings?

[sTAPler27]

See above

 

[Klajwert]

All wonders are "Ageless", so they provide their bonuses through all eras.

 

[Evolena]

But Districts with older Buildings are no longer Quarters, so no, only for a full Ageless Quarter or with new Buildings.