Hagia Sophia, the Basilica Cistern, the Blue Mosque and Topkapı Palace are neighbours in Sultanahmet, on İstanbul's historic peninsula, and all four can be seen on foot in a single day. The ground suggests an order. Begin with Hagia Sophia; go next to the cistern on Soğukçeşme Sokağı, south-west of it; cross the park to the Sultan Ahmed Mosque and the line of the old Hippodrome beside it; and finish at Topkapı, whose Imperial Gate stands behind Hagia Sophia and whose outer walls take in Hagia Irene and the Tiled Kiosk of the Archaeological Museums. Every building has its own hours and ticket, listed on its page.
Hagia Sophia: the third building on the site
Two churches came before the one you walk into. Constantius built the first in 360 and it was known as the Megale Ekklesia, the Great Church; Hagia Sophia, meaning Holy Wisdom, became its name in the fifth century. Theodosius II put up a replacement in 415, and riots destroyed them both. The present building is Justinian's. The records say his architects, Isidoros of Miletos and Anthemios of Tralles, directed a hundred master builders with a hundred men each, and the job took five years and ten months.
Everything inside is organised around the dome, wider than was normal in its day and built of special bricks, light and strong enough to hold through earthquakes. At its crown, in a circle 11.3 metres across, runs the thirty-fifth verse of the Surat an-Nur, the work of Kazasker Mustafa İzzet Efendi during the repairs of 1847 to 1849, which the Swiss Fossati brothers carried out for Sultan Abdülmecid.
The oldest mosaics, in the narthex, have no figures; the figured ones are believed to have been taken down in the iconoclast years, and the apse mosaic was the first made after that era closed in 843. The Ottomans added mihrabs, a minbar and galleries for the müezzins inside, and outside a ring of buildings, a primary school, a medrese, sundials and a timekeeper's room among them. A church for 916 years, it became a mosque in 1453, a museum in 1934, and has been used as a mosque again since 2020.
The story of those changes is told in a separate building at Sultanahmet, the old Defter-i Hakani Nezareti, now the Hagia Sophia History and Experience Museum: 1,700 years in thirteen halls with narration in 23 languages, and ground-floor windows that look into a Byzantine cistern.
The Basilica Cistern
Next to the Milion, the stone the Byzantine empire took as the zero point of the world, the Basilica Cistern was dug for Justinian in 526–27. In Turkish it is Yerebatan Sarayı, the sunken palace, for the marble columns rising out of its water; the other name recalls a basilica that once stood on top. Eckhard Unger, the German archaeologist who first measured it during the First World War, gave 138 by 64.6 metres, and it holds about 100,000 tons of water.
Its brick vaults rest on three hundred and thirty-six columns, twenty-eight rows one way and twelve the other, while forty-one more are hidden in a north-west section walled off under Abdülhamid II. Look among them for the decorated shafts, the Corinthian capitals and the Medusa heads placed upside down.
The Blue Mosque and its complex
Across the park, the Sultan Ahmed Mosque was begun in 1609 for Ahmed I by Sedefkâr Mehmet Ağa, one of the architects Sinan trained. The blue tiles of its walls, made in İznik and Kütahya in the underglaze technique, gave it its popular name. Its prayer hall is 64 metres by 72, and the central dome is 23.5 metres wide and 43 high. The six minarets are of küfeki stone: two rise from the courtyard corners and four from those of the hall itself.
The mosque is the heart of one of the largest building groups in the city, which once took in a hospital, a han, a bath, a medrese, a coffee house and a covered market street, most of it still standing. The sultan's pavilion at the south-east corner, a building type that first appears in Ottoman architecture here, now holds the Carpet Museum, which the Directorate General of Foundations describes as the only museum in Türkiye given over entirely to carpets. Its 448 carpets reached mosques as pious gifts over the centuries; 62 are shown in rotation, the earliest from the 14th century. On the north side, facing Hagia Sophia, is the single-domed tomb of Ahmed I, where Kösem Sultan, Osman II and Murad IV also lie; most people walk past it without going in.
The Hippodrome, the İbrahim Paşa Palace and the palace mosaics
When Constantine refounded the city he gave it a forum, a palace and a hippodrome. The mosque complex has a side that faces the Hippodrome, and there its shops stand on the Sphendone, the curved wall that closed its southern end. Facing the square from the west, the İbrahim Paşa Palace is the one palace built for a subject rather than a sultan that has come down to us; raised on arches around a terrace, it has housed the Museum of Turkish and Islamic Arts since 1983, with Seljuk carpets of the thirteenth century among its treasures.
The covered market street of the mosque, the Arasta, was built over part of the Great Palace, and the Great Palace Mosaics Museum shows the floor of the palace's colonnaded courtyard where it was laid, under Justinian I. Ninety scenes and 150 figures of people and animals fill it: hunters facing a tiger, a boar and a lion, shepherds, peasants at work and children playing, without a single caption. Every square metre needed about 40,000 cubes of stone, glass and terracotta, each five millimetres across.
Topkapı Palace and Hagia Irene
Over Topkapı's Imperial Gate, the Bâb-ı Hümâyûn, an inscription dates the fortress to Ramadan 883 of the Hegira, which fell in November or December 1478, and names Mehmed II as its builder. The palace was once home to close to four thousand people, and its early grounds of roughly 700,000 square metres have shrunk to 80,000. Its two parts match its two roles, the Birun for the service buildings and the Enderûn for the inner household. As a museum it opened on 9 October 1924, and in 2024 it counted 4,683,250 visitors.
Inside the outer walls stands Hagia Irene, which the portal calls the first church of Byzantium, founded by Constantine in the 330s over Roman temples. Fire took it in 532 and again in 564, it was repaired three times, and its walls stayed bare because icons were then forbidden. The Ottomans kept their weapons in it, and later opened in it the first museum their state had.
The Archaeological Museums and Gülhane
The İstanbul Archaeological Museums, which the ministry calls the first museum in Türkiye, hold close to a million objects in three buildings reached from the Gülhane stop. The Tiled Kiosk of 1472 is the one survivor of three kiosks Mehmed II built in the outer gardens, in a Timurid manner whose glazed brick recalls the Bibi Khanum mosque in Samarkand. The Museum of the Ancient Orient, in a building of 1883 by Alexander Vallaury, has the victory stele of Naram-Sin, the Treaty of Kadesh and glazed panels from Babylon's Ishtar Gate, and the main museum keeps the sarcophagi, the Alexander sarcophagus first among them. In Gülhane Park, the former imperial stables house working models of instruments devised by Muslim scholars from the ninth century to the sixteenth, a collection prepared by Fuat Sezgin.
With one day, the order above keeps the walking short. With two, give the second to Topkapı, Hagia Irene and the Archaeological Museums; Hagia Irene and the Tiled Kiosk both stand inside the palace's outer walls.
