//
Photo: Antoloji, CC BY-SA 4.0 via Wikimedia Commons
The Byzantines built several great palaces in Constantinople and this is the only one to survive almost intact. It's from the late 13th century, in typical alternating marble and red-brick rows, and was an imperial residence: Porphyrogenitus means "born to the purple" indicating the heir to the crown. Yet it was merely an annex or pavilion within the much greater Palace of Blachernae, of which nothing else remains. It's set within the north end of the Theodosian Walls and was much bashed during the Ottoman capture. Later it was variously a menagerie, brothel, pottery, poorhouse and bottle works, then fell derelict in the 20th century. In 2021 it re-opened as a museum.
The Palace of the Porphyrogenitus, known in Turkish as the Tekfur Sarayı, is a late 13th-century Byzantine palace in the north-western part of the old city of Constantinople. An annex of the greater palace complex of Blachernae, it is the best preserved of the three Byzantine palaces to survive in the city, and one of the few relatively intact examples of late Byzantine secular architecture in the world.
© OpenStreetMap contributors
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.
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.
Sveti Stefan Kilisesi
A remarkable Bulgarian Orthodox church better known as Demir Kilise, "Iron Church", as it's a cast iron prefab. The Bulgarians split from the Greek Orthodox and established their own wooden church in 1870, which burned down. The ground was too weak for a masonry or concrete structure so they opted for cast iron. The sections were cast in Vienna, shipped here and assembled, to open in 1898. The church was renovated in 2018, but the archpatriarchate building across the street remains a gaunt shell.
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.
Turkish: Aya Yorgi, Greek: Agíou Geōrgíou
This is modest from the outside, as the Ottomans would not permit non-Muslim religious buildings to rival the mosques. The interior is lavish but its chief importance is as the senior Eastern Orthodox church. Their Patriarchate has been housed here since 1586 when they were ejected from Agia Sophia.