Cathedral of Avan
Avan District, Armenia · built 591
The Cathedral of Avan (Avani kat′oghike) is a ruined late 6th-century church located in the Avan District of Yerevan, the capital of Armenia. It is the oldest surviving church inside Yerevan's city limits, and earliest dated example of tetraconch church.
Church data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).