The Chora Museum, originally known as the Church of the Holy Saviour in Chora, is one of the most stunning examples of Byzantine art and architecture in Istanbul. Located outside the old city walls, the word “Chora” means “countryside” in Greek — a reference to its position beyond the ancient city limits. The building dates back to the 4th century, but its most famous mosaics and frescoes were added in the 14th century, during the final years of the Byzantine Empire. These masterpieces depict the life of Jesus and the Virgin Mary with incredible realism and emotional depth. After the Ottoman conquest, it was converted into a mosque, later became a museum in the 20th century, and today stands as a UNESCO-recognized monument, admired for its brilliant mosaics, frescoes, and spiritual atmosphere.

The Fethiye Museum, originally known as the Church of Theotokos Pammakaristos, is one of the most beautiful surviving Byzantine churches in Istanbul. Built in the 11th–12th centuries, it served as the seat of the Greek Orthodox Patriarchate after the Ottoman conquest of the city, until the early 17th century. In 1591, it was converted into a mosque and renamed Fethiye (meaning “of the Conquest”) Mosque to commemorate Ottoman victories in the Caucasus. Part of the complex was later turned into a museum, showcasing exquisite Byzantine mosaics similar in style to those of the Chora Church. Today, Fethiye Museum stands as a serene and historically rich site, reflecting Istanbul’s multilayered cultural and religious heritage.

The Church of St. Mary of the Mongols, also known as Kanlı Kilise, is one of the most remarkable and historically significant Greek Orthodox churches in Istanbul. Located in the Fener district, it was built in the 13th century by Maria Palaiologina, the daughter of Byzantine Emperor Michael VIII, who was once married to the Mongol ruler Abaqa Khan — hence the name “of the Mongols.” What makes this church unique is that it is the only Byzantine church in Istanbul that has never been converted into a mosque after the Ottoman conquest in 1453. It remains an active Greek Orthodox place of worship, representing the continuity of Byzantine religious life in modern-day Istanbul. Its red-brick façade and serene courtyard make it a hidden gem for visitors exploring the historic Fener area.

The Fatih Mosque, located in the heart of Istanbul’s historic peninsula, is one of the most important examples of early Ottoman architecture. It was commissioned by Sultan Mehmed II (Mehmed the Conqueror) in the 15th century, soon after his conquest of Constantinople, and built on the site of the former Church of the Holy Apostles, one of Byzantium’s most sacred churches. The complex originally included madrasas, a library, a hospital, and a caravanserai — symbolising the power and cultural vision of the newly founded Ottoman capital. Although damaged by earthquakes and rebuilt in the 18th century, it still stands as a monumental symbol of Ottoman faith, scholarship, and imperial legacy.

The Zeyrek Mosque, originally built as the Monastery of the Pantokrator, is one of the most significant surviving Byzantine religious complexes in Istanbul. Constructed in the 12th century by Empress Irene of Hungary, wife of Emperor John II Komnenos, it originally consisted of three connected churches — dedicated to Christ Pantokrator, the Virgin Mary, and the Archangel Michael. After the Ottoman conquest, it was converted into a mosque and became known as Molla Zeyrek Camii, named after the scholar Molla Zeyrek Mehmed Efendi, who taught in the nearby madrasah. Today, the Zeyrek Mosque stands as a powerful symbol of Byzantine architecture meeting Ottoman faith, and it offers one of the most beautiful panoramic views over the Golden Horn.

The Ahrida Synagogue, located in the historic Balat district of Istanbul, is the oldest and largest functioning synagogue in the city. It was built in the 15th century by Sephardic Jews who settled in the Ottoman Empire after being expelled from Ohrid (present-day North Macedonia) — the origin of its name, Ahrida. The synagogue is famous for its unique bimah (reading platform) shaped like the prow of a ship, symbolising either Noah’s Ark or the ships that brought the Sephardic Jews safely to Ottoman lands. Still active today, the Ahrida Synagogue remains a spiritual and cultural centre for Istanbul’s Jewish community and a remarkable reminder of the city’s multicultural and religious harmony throughout history.

The Ecumenical Patriarchate of Constantinople, located in the Fener district of Istanbul, is the spiritual centre of the Eastern Orthodox Church and the residence of the Ecumenical Patriarch, considered the spiritual leader of over 300 million Orthodox Christians worldwide. After the Ottoman conquest of Constantinople in 1453, the Patriarchate was moved from the Church of the Holy Apostles to its current location in Fener, where it has remained ever since. The complex includes the Church of St. George (Aya Yorgi), which serves as the main patriarchal cathedral. Inside, visitors can see beautiful icons, relics of saints, and the Patriarchal Throne — symbols of centuries-old Orthodox tradition. Today, the Patriarchate continues to play an important role as a bridge between faiths and cultures, preserving the spiritual and historical legacy of Byzantine Christianity in modern Istanbul.