Palace Chapel (Buda Castle)
The medieval Palace Chapel (Hungarian: Várkápolna; formerly Alamizsnás Szent János-kápolna) in Buda Castle was built in the 15th century by King Sigismund as the lower chapel of the former Castle Church. The Gothic chapel, which survived the destruction of the 1686 siege, was buried under a Baroque terrace for centuries.
Source: Wikipedia — Palace Chapel (Buda Castle) (CC BY-SA 4.0)