Mor Ephrem Syriac Orthodox Church

The third and grandest of the churches on this site, completed in 537 AD. The 30-m diameter dome covers what was for over 1000 years the largest enclosed space in the world, only surpassed in 1520 by Seville cathedral. It used "pendentive" architecture to throw the dome's weight onto four stout pillars, a design that inspired many Eastern Orthodox churches and Ottoman mosques. It became a mosque after the Ottoman conquest in 1453, remaining so until 1931. It was then a museum until 2020 when it was again proclaimed a mosque. That means you must work around prayer times and dress appropriately.

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 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.

A medieval citadel on the Bosphorus at the mouth of the Göksu creek. It was built in the late 14th century to control (polite word for "choke off") shipping along the Bosphorus, which narrows to 660 m at this point. It worked in tandem with Rumeli Citadel, built some 50 years later on the European bank. It fell into disrepair but was restored in the 1990s. You can't go in, but it's a pleasant setting; the entire village is named Anadolu Hisarı after the fort and has many traditional wooden houses (yalı). Ferries along the Bosphorus call here.

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 only active Ashkenazi Synagogue open to visits and prayers.

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.

Tiny house museum on the life of Turkish novelist Orhan Kemal (1914–1970).

The defining image of Istanbul, dominating the skyline with its great dome and six minarets. Completed in 1617 for Sultan Ahmed I, it's still a working mosque, so dress appropriately and avoid prayer times. Enter via the courtyard on the SW side. You step (shoeless) into the blue-tiled prayer hall beneath the main dome and its semi-domes. The mihrab is of finely carved marble, well-lit, and the minbar (pulpit) next to it is visible from almost all parts.

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.

Opened in 2012, this museum is unique and a must-see when you are in the Beyoğlu area. It was created by Turkish Nobel laureate Orhan Pamuk alongside a novel of the same name. It tells the love story of the two main characters from the novel, and represents life in Istanbul during the late 1970s to early 1980s, as it exhibits thousands of objects from that era.

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.

A contemporary art museum in a building converted from an old power plant: 1914-built and coal-fired, this was the oldest in Istanbul and the Ottoman Empire. Part of the plant was kept in almost exact original condition and now serves as the "Energy Museum".

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.

Built in 1564 by Mimar Sinan for Rüstem Pasha, Grand Vizier of Suleiman the Magnificent, this small mosque has an interior covered by beautiful Iznik pottery, then at its zenith.

Situated on the gentle hill overlooking the neighbourhood of Emirgan and the Bosphorus, Emirgan Park was for long the only place in the city where Istanbulites can admire the beauty of tulips. Having lost that distinction since the first decade of the 2000s as tulips are now everywhere, this is still a beautiful park with artificial ponds, small waterfalls, and impressive views of the Bosphorus. There are also cafes with open-air sections housed in pleasant former imperial hunting manors. Squirrels are there, too, in the middle of this metropolis of more than 15 million people, though you may have to look a bit deeper (or a bit upper on the branches!) to spot them.

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.