Hagia Sophia, officially the Hagia Sophia Holy Grand Mosque, and formerly the Church of Hagia Sophia, 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 became the city's Latin Catholic cathedral. In 1453, after the Fall of Constantinople to the Ottoman Empire, it was converted into a mosque. In 1935, the secular Turkish Republic established it as a museum. In 2020, it re-opened as a mosque.

The Topkapı Palace, or the Seraglio, is a large museum in the east of the Fatih district of Istanbul in Turkey. In the 15th and 16th centuries it served as the main residence and administrative headquarters of the Ottoman sultans.

Sultan Ahmed Mosque (Turkish: Sultan Ahmet Camii), also known as the Blue Mosque, is an Ottoman-era historical imperial mosque located in Istanbul, Turkey. A functioning mosque, it also attracts large numbers of tourist visitors. It was constructed between 1609 and 1616 during the rule of Ahmed I. Its Külliye contains Ahmed's tomb, a madrasah and a hospice. Hand-painted blue tiles adorn the mosque’s interior walls, and at night the mosque is bathed in blue as lights frame the mosque’s five main domes, six minarets and eight secondary domes.It sits next to the Hagia Sophia, the principal mosque of Istanbul until the Blue Mosque's construction and another popular tourist site. The Blue Mosque was included in the UNESCO World Heritage Site list in 1985 under the name of "Historic Areas of Istanbul".