Bodrum Camii ( Church of the Myrelaion ), Istanbul.

41.008570,28.955500

Before he became Emperor in 920, Romanus I Lecapenus had aquired land at a place called Myrelaion ( the place of myrrh ), upon which lay the ruins of a circular structure from a former era. This Romanus converted into a cistern and above which he built a palace, next to which he later built a monastery. The monastery church, seen here, was converted into a mosque in about 1500 by Grand Vizier Mesih Paşa, and over time became known as Bodrum Camii, after its basement substructure [crypt].
Having been abandoned after fire in 1911, the structure was subjected to robust partial restoration in the 1960s.
It was finally restored and reopened as a mosque in 1986.
View from the north-west. Access off Mesihpaşa Caddesi.