Hagia Irene (Aya Irini), former Byzantine church of 6th century, is opened to public as a museum as of April 2014. The site is located in the first courtyard of Topkapi Palace in Istanbul.
Entrance to the museum costs 20 Turkish Liras. It's closed on Tuesdays, same as Topkapi palace museum. During summer months it can be visited between 09:00-18:00 (last entry).