Çengelköy

Started in 1613 by the Ottoman sultan Ahmet I (r. 1603–1617, who also had the Blue Mosque in the Old City built), and extensively renovated by the art-loving Selim III (r. 1789–1807), this sole building, which itself has the distinction of being the only intact structure that dates back to the rule of Ahmet III (r. 1703–1730), set inside a beautiful garden of pools and mature cedar and magnolia trees is the only remaining part of what was once the fourth largest palatial complex in Istanbul, extending all the way to the banks of the Golden Horn (which is now occupied by the derelict buildings of the closed shipyard, which also block part of the view towards the shore). According to the local rumour, its name (which in Turkish means "mirrored poplar") derives from the now absent mirrors gifted by Venice to the palace that were presumably "as tall as the poplars" (aynalar kavak). The highly decorative and colourful interior includes several rooms of original furnitures fit for a sultan, some of which are covered with nacre, and walls embellished with Ottoman poems praising the palace and Selim III. Downstairs is a small museum dedicated to music, which exhibit some of the instruments (violins, ouds, and kamanchehs) and gramophone records owned by Fatma Gevheri Sultana (1904–1980), the granddaughter of Abdülaziz I (r. 1861–1876). While you are outside, also check out the old main entrance (now closed) towards the Golden Horn, topped by a dome. Worth the half hour spent there.

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.

Built circa 1200 as the Eastern Orthodox Theotokos Kyriotissa Church, after the Ottoman conquest it was handed over to the Qalandari, a Sufi sect. In the mid-18th century it was converted to a Sunni mosque, and its mosaics were plastered over. The original appearance was restored in the 1970s.

Sokollu Mehmet Pasha was the grand vizier and de facto ruler of the Ottoman Empire during its 16th century golden age. He commissioned this mosque, one of three in the city to bear his name, but the sloping site was a challenge. He hired the best, Mimar Sinan, who completed it in 979 AH / 1571 AD, with the slope resolved by a fronting courtyard above shops and a medrese. The interior has outstanding İznik blue tiles, and three fragments of the Black Stone (Hajar al-Aswad) of the Kaaba: above the main entrance, minbar and mihrab.

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 rediscovered in 2010 when an overlying building was demolished. It was built circa 430 AD to store water brought in by Valens Aqueduct. It's smaller than the better-known Basilica Cistern, but better lit, more atmospheric and less touristy.

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.

This is a triple structure: the church of the Monastery of Pantokrator built 1118, then a public church circa 1136 plus a chapel that served as a royal mausoleum. It became a mosque and medresse in Ottoman times, but without massive alteration so it's a prime example of middle-Byzantine architecture. It's nowadays again a mosque, photogenic by day or dusk but the area should be avoided at night.

Although not at the size of Hagia Sophia, this is the largest active church in Turkey. It’s directly on Istiklal St, but somewhat hidden from view by its yard portal. Catholic Masses in Italian, Turkish, and English (in different days of the week).

Feshane began as a factory producing fezzes (fes), the red hats made of felt adopted by the Ottomans in the early 19th century as a part of westernizing efforts in lieu of much more traditional turbans. However, the fez was scrapped in favour of western garments during Atatürk's reforms of the 1920s and 30s as it was thought to symbolize the old, decidedly oriental regime. A restoration in 1998 made it a cultural and exhibition center, and after another in 2023, it was reopened as a culture and art center under the name Artistanbul Feshane.

A neo-gothic Anglican cathedral which would not be out of place in northwestern Europe, the Crimean Memorial Church was built for the Protestant community of the city by Britain in the late 19th century. It was named in honour of the soldiers died in the Crimean War of 1856, fought against Russia by the allied Ottoman and British Empires. The congregation of the church today mostly consists of Anglican East Asians and Sri Lankans resident in Istanbul.

A former synagogue, the museum's exhibit details how the cultures mixed with and influenced each other in the past 500+ years since the Spanish expulsion.

Turkey was slow to protect its antiquities and to display them properly, but in 1867 Sultan Abdülaziz toured the museums of Paris, London and Vienna and saw what was needed. The main collection is in a grand neo-classical building of 1891, with two annexes for ancient art and Islamic art. Exhibits include Sumerian tablets, pieces of the wall of Babylon, Roman statues, and the sarcophagus of Alexander the Great, which he never lay in.

This lavish palace with 285 rooms and 43 halls was the admin centre for the Ottoman Empire in its last 60 years. The palace government block (Selamlık) includes the Imperial Mabeyn (State Apartments) and Muayede Hall (Ceremonial Hall), while the Imperial Harem was the sultan's private quarters. Also here are the Painting Gallery, Music Museum, Clock Museum and Museum of Palace Collections. Free audio guide in several languages available by the ticket office. No photography inside, no backpacks but you can leave them in the cloakroom. Allow 3 hours to see everything.

This attractive neighbourhood was home to a large Christian and Jewish population until some decades ago and still has a number of sights like two synagogues, some churches among which the Armenian Surp Krikor Lusavoriç, dozens of wooden houses and a Jewish and Christian cemetery.

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.

A nice, organized museum with contemporary installations. It may be seen as overpriced given its small size. It also has a simple cafe.