Aya Yorgi Greek Orthodox Church in Fener is also known as the Patriarchal Church of St. George, the main church of the Ecumenical Patriarchate of Constantinople. Its modest exterior contrasts with its richly decorated interior, holy relics, icons, and deep importance for the Greek Orthodox world.

Bulgarian St. Stephen Church, located in Balat, is famous as the “Iron Church” because it was built largely from prefabricated iron elements. Completed in 1898, it stands as an important symbol of the Bulgarian Orthodox community and its struggle for religious independence in Istanbul.

Aya Panteleymon Russian Orthodox Church is one of Karaköy’s historic Russian rooftop churches, connected to the Russian Orthodox community in Istanbul. Before World War I, Russian pilgrims traveling to Jerusalem often stopped here, and the church still preserves icons and frescoes dedicated to St. Panteleymon.

St. Esprit Cathedral, located in Harbiye, is one of the most important Roman Catholic churches in Istanbul. Consecrated in 1846, it serves as the seat of the Latin Catholic leadership in the city and has been visited by several popes.

Uc Horan Armenian Church is a major Armenian landmark in Beyoğlu. Designed by Garabet Balyan, Hamamcıbaşı Minas Agha, and Hovhannes Serveryan, it reflects the multicultural Christian heritage of 19th-century Istanbul.

St. Anthony of Padua Basilica on İstiklal Avenue is one of the largest and best-known Roman Catholic churches in Istanbul. The current church was opened in 1912 and is noted for its impressive Neo-Gothic style and strong connection to Istanbul’s historic Italian Catholic community.

Santa Maria Draperis Church is one of Istanbul’s oldest Roman Catholic parishes, founded in 1584. Located on İstiklal Avenue below street level, it is known for its neoclassical entrance, marble altar, and long Franciscan history.