Old Darülfünun building

Sultanahmet Jail (Turkish: Sultanahmet Cezaevi), a former prison in Istanbul, Turkey, is now the luxury Four Seasons Hotel at Sultanahmet. It is located in Sultanahmet neighborhood of Fatih district on the historical peninsula.

The Historic Areas of Istanbul are a group of sites in the capital district of Fatih in the city of Istanbul, Turkey. These areas were added to the UNESCO World Heritage List in 1985. This World Heritage Site includes buildings and structures such as the Sarayburnu, the Topkapı Palace, the Hagia Sophia, the Sultan Ahmed Mosque, the Hagia Irene, Zeyrek Mosque, Süleymaniye Mosque, Little Hagia Sophia and the Walls of Constantinople.

Hagia Sophia (Turkish: Ayasofya; Koinē Greek: Ἁγία Σοφία, romanized: Hagía Sophía; Latin: Sancta Sophia, lit. 'Holy Wisdom'), officially known as the Hagia Sophia Grand Mosque (Turkish: Ayasofya-i Kebir Cami-i Şerifi) and formerly as the Church of Holy Wisdom (Greek: Ναός της Αγίας του Θεού Σοφίας, romanized: Naós tis Ayías tou Theoú Sofías), is a Late Antique place of worship in Istanbul, designed by the Greek geometers Isidore of Miletus and Anthemius of Tralles. Built in 537 as the patriarchal cathedral of the imperial capital of Constantinople, it was the largest Christian church of the eastern Roman Empire (the Byzantine Empire) and the Eastern Orthodox Church, except during the Latin Empire from 1204 to 1261, when it temporarily became a Roman Catholic cathedral. In 1453, after the Fall of Constantinople to the Ottoman Empire, it was converted into a mosque. In 1935, the Republic of Turkey established it as a museum. In 2020, it was reconverted into a mosque. Built by the eastern Roman emperor Justinian I as the Christian cathedral of Constantinople for the state church of the Roman Empire between 532 and 537, the church was then the world's largest interior space and among the first to employ a fully pendentive dome. It is considered the epitome of Byzantine architecture and is said to have "changed the history of architecture". The present Justinianic building was the third church of the same name to occupy the site, as the prior one had been destroyed in the Nika riots. As the episcopal see of the ecumenical patriarch of Constantinople, it remained the world's largest cathedral for nearly a thousand years, until Seville Cathedral was completed in 1520. Beginning with subsequent Byzantine architecture, Hagia Sophia became the paradigmatic Orthodox church form, and its architectural style was emulated by Ottoman mosques a thousand years later. It has been described as "holding a unique position in the Christian world" and as an architectural and cultural icon of Byzantine and Eastern Orthodox civilization.The religious and spiritual centre of the Eastern Orthodox Church for nearly one thousand years, the church was dedicated to the Holy Wisdom. It was where the excommunication of Patriarch Michael I Cerularius was officially delivered by Humbert of Silva Candida, the envoy of Pope Leo IX in 1054, an act considered the start of the East–West Schism. In 1204, it was converted during the Fourth Crusade into a Catholic cathedral under the Latin Empire, before being returned to the Eastern Orthodox Church upon the restoration of the Byzantine Empire in 1261. The doge of Venice who led the Fourth Crusade and the 1204 Sack of Constantinople, Enrico Dandolo, was buried in the church. After the Fall of Constantinople to the Ottoman Empire in 1453, it was converted to a mosque by Mehmed the Conqueror and became the principal mosque of Istanbul until the 1616 construction of the Sultan Ahmed Mosque. Upon its conversion, the bells, altar, iconostasis, ambo, and baptistery were removed, while iconography, such as the mosaic depictions of Jesus, Mary, Christian saints and angels were removed or plastered over. Islamic architectural additions included four minarets, a minbar and a mihrab. The Byzantine architecture of the Hagia Sophia served as inspiration for many other religious buildings including the Hagia Sophia in Thessaloniki, Panagia Ekatontapiliani, the Şehzade Mosque, the Süleymaniye Mosque, the Rüstem Pasha Mosque and the Kılıç Ali Pasha Complex. The patriarchate moved to the Church of the Holy Apostles, which became the city's cathedral. The complex remained a mosque until 1931, when it was closed to the public for four years. It was re-opened in 1935 as a museum under the secular Republic of Turkey, and the building was Turkey's most visited tourist attraction in 2015 and 2019. In July 2020, the Council of State annulled the 1934 decision to establish the museum, and the Hagia Sophia was reclassified as a mosque. The 1934 decree was ruled to be unlawful under both Ottoman and Turkish law as Hagia Sophia's waqf, endowed by Sultan Mehmed, had designated the site a mosque; proponents of the decision argued the Hagia Sophia was the personal property of the sultan. This redesignation drew condemnation from the Turkish opposition, UNESCO, the World Council of Churches, the International Association of Byzantine Studies, and many international leaders.

The Hagia Sofia Mansions Istanbul, Curio Collection by Hilton, previously known as Hotel Yeşil Ev, (literally: Hotel Green House) is a historic wooden mansion, located in the Sultanahmet neighborhood of Istanbul, Turkey, which is used as a hotel after restoration. The premises is run by the Dorak Holding.

The Augustaion (Greek: Αὐγουσταῖον) or, in Latin, Augustaeum, was an important ceremonial square in ancient and medieval Constantinople (modern Istanbul, Turkey), roughly corresponding to the modern Aya Sofya Meydanı (Turkish, "Hagia Sophia Square"). Originating as a public market, in the 6th century it was transformed into a closed courtyard surrounded by porticoes, and provided the linking space between some of the most important edifices in the Byzantine capital. The square survived until the late Byzantine period, albeit in ruins, and traces were still visible in the early 16th century.

The Fountain of Sultan Ahmed III (Turkish: III. Ahmet Çeşmesi) is a fountain in a Turkish rococo structure in the great square in front of the Imperial Gate of Topkapı Palace in Istanbul, Turkey. It was built under Ottoman sultan Ahmed III in 1728, in the style of the Tulip period. It was a social centre and gathering place during the Ottoman period of Constantinople.

The 740 Constantinople earthquake took place on 26 October, 740, in the vicinity of Constantinople and the Sea of Marmara. In Constantinople, the earthquake caused the collapse of many public buildings. The Walls of Constantinople were also damaged. The casualties in Constantinople reportedly included over 1,000 people. The earthquake reportedly destroyed a number of towns in Thrace. It also damaged the cities of Nicaea (İznik), Nicomedia (İzmit), and Praenetus. The historians Theophanes the Confessor (8th-9th century) and George Kedrenos (11th century) reported that the earthquake caused the sea to retire away from the coast in many places. The sea soon returned, and flooded many towns. The description given matches that of a seismic sea-wave (tsunami). The date of the earthquake is recorded by (among others) Anastasius Bibliothecarius (9th century), Joannes Zonaras (12th century), Carolus Sigonius (16th century), Caesar Baronius (16th-17th century), and Sethus Calvisius (16th-17th century).

Soğukçeşme Sokağı (literally: Street of the Cold Fountain) is a small street with historic houses in the Sultanahmet neighborhood of Istanbul, Turkey, sandwiched in-between the Hagia Sophia and Topkapı Palace. The car-free zone street is named after the fountain situated at its end towards Gülhane Park. The wooden, two or three-storey Ottoman houses consisting of four to ten rooms date to the 19th to 20th century, and have been restored with the initiative of Çelik Gülersoy in 1985-1986. Called "Ayasofya Konakları" (Hagia Sophia Mansions), nine of the houses are part of the hotel Hagia Sofia Mansions Istanbul, Curio Collection by Hilton. The houses are named after the flower shrubs next to them as "Yaseminli Ev" (Jasmine House), "Mor Salkımlı Ev" (Wisteria sinensis House), "Hanımeli Ev" (Honeysuckle House) etc. The buildings are decorated in the 19th-century style with furniture including such items as beds and consoles, silk curtains, velvet armchairs and gilded mirrors. Most notable guest of the hostel was Queen Sofía of Spain, who stayed in the spring of 2000 for four nights.The birthplace of Turkey's 6th president Fahri Korutürk (1903–1987) is also situated in this street. One of the houses hosts the library "İstanbul Kitaplığı" with over 10,000 books about Istanbul owned by the Çelik Gülersoy Foundation. On one end of the street towards Gülhane Park is a Byzantine cistern, which houses the "Sarnıç Restaurant" today.

The Milion (Greek: Μίλιον or Μίλλιον, Míllion; Turkish: Milyon taşı) was a monument erected in the early 4th century AD in Constantinople (modern-day Istanbul, Turkey). It was the Byzantine zero-mile marker, the starting-place for the measurement of distances for all the roads leading to the cities of the Byzantine Empire. It thus served the same function as the Golden Milestone (Milliarium Aureum) in Rome's forum. The domed building of the Milion rested on four large arches, and it was expanded and decorated with several statues and paintings. It survived the Fourth Crusade and Ottoman conquest of Constantinople in 1453 but had disappeared by the start of the 16th century. During excavations in the 1960s, some partial fragments of it were discovered under houses in the area.

The area around Constantinople was affected by a major earthquake in AD 447. It caused serious damage to the recently completed Theodosian Walls in Constantinople, destroying 57 towers and large stretches of the walls. The historical records contain no mention of casualties directly associated with this earthquake, although many thousands of people were reported to have died in the aftermath due to starvation and a "noxious smell".

The Basilica Cistern, or Cisterna Basilica (Turkish: Yerebatan Sarnıcı or Yerebatan Saray, "Subterranean Cistern" or "Subterranean Palace"), is the largest of several hundred ancient cisterns that lie beneath the city of Istanbul, Turkey. The cistern, located 150 metres (490 ft) southwest of the Hagia Sophia on the historical peninsula of Sarayburnu, was built in the 6th century during the reign of Byzantine Emperor Justinian I. Today it is kept with little water, for public access inside the space.

The Zeynep Sultan Mosque (in Turkish Zeynep Sultan Camii) is a mosque built in 1769 by Ayazma Mosque's architect Mehmet Tahir Ağa for Ahmed III's daughter Zeynep Sultan. It evokes Byzantine churches because of its architectural style and materials that were used in its construction.