Massive historic building that is over 1500 years ...

Massive historic building that is over 1500 years olds. It was originally a church for over 900 years and then as a mosque for almost 500 years. It is now a museum. Some effort has been kept to maintain what remains of the Christian mosaics and the roof. It is under significant maintenance due to wear and tear but there area still a good few hundred years of life in this building.