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Photo: Vivaystn, CC BY-SA 4.0 via Wikimedia Commons
This is a circular indoor space enclosed by a 3D depiction of the Ottomans breaching the Walls of Constantinople on 29 May 1453, with sound effects. It's over-priced, unhistorical and tourist-trappy.
The Panorama 1453 Historical Museum is a historical museum in Istanbul that opened on 31 January 2009.
© OpenStreetMap contributors
Sümbül Efendi Mosque
Built in the early 5th century as a monastery dedicated to Saint Andrew the Apostle, in 766 it was the burial place of Saint Andrew of Crete and was later re-dedicated to him. It was rebuilt in the late 9th century and again in the 13th, then around 1490 converted into a mosque. From the 16th century it was occupied by the Dervishes, when the legend arose that a chain hung to a cypress tree in the courtyard was a truth diviner. The chain was swung between rival witnesses and the one it hit was telling the truth. The cypress stump is still standing.
The original mosque was built between 1463-1470 by the Greek architect Atik Sinan, by order of Sultan Mehmet II the Conqueror, on the site of the former Church of the Holy Apostles, which had served as Byzantine Imperial burial place for a thousand years. The grand complex with eight medreses, a library, hospital, hospice, caravanserai, market, hamam, primary school and public soup kitchen was smashed again and again by earthquakes, and the present building is from 1771 to a different design. The interior is lavish, and outside is the ornate tomb of Mehmet II and his wife Gülbahar Hatun.
Pammakaristos Church
The Church of Theotokos Pammakaristos ("All-Blessed Mother of God") was built between the 11th and 12th centuries. The parekklesion or side-chapel was added maybe 1300, with rich mosaics. The main building became a mosque in 1591, named for Sultan Murad III's conquest (fetih, hence Fethiye) of Georgia and Azerbaijan: the interior was opened up, but the chapel was undisturbed and in modern times became a museum. In 2020 the entire building was proclaimed a mosque, and every scrap of Byzantine artistry was covered up, so now there's nothing worth seeing.
This was built in the 1430s by Grecian Jews ("Romaniotes") from the city of Ohrid, now in North Macedonia. The district of Balat was a Jewish quarter, swelled from 1492 by those expelled from Spain. The synagogue is only open for pre-arranged tours.
Turkish: Özel Fener Rum Lisesi, Greek: Μεγάλη του Γένους Σχολή
This is the red-brick castle seen south of St George. Built 1881/83, it teaches the standard Turkish curriculum plus Greek language and culture, and the tower houses an observatory. No visits.