Hagia Sophia is one of the most valuable structures in the world in terms of art and architecture. Considering its religious importance, one of the world's most valuable cultural assets emerges. Hagia Sophia is both the world's oldest cathedral and the world's fastest built cathedral. It still remains the 4th largest cathedral in the world today.

 This building, which is remembered as the Bloody Church, also has an interesting story. They say; The Emperor has an illegitimate daughter and the Emperor marries her to the Mongol Han to make an alliance with the Mongols. Han died before they could get married. After Han's death, the girl returns to her father's side and has built this church. After she has it built, she dedicates herself to this church.

Neve Shalom Synagogue is the largest synagogues in Istanbul. Unlike other synagogues in Istanbul, the synagogue is very active, where Shabbat (Jewish rites), weddings, funerals, Bar Mitzvahs, Circumcision and religious holidays are held and also this build targeted by terrorist attacks in the past.

It is the oldest known church in Istanbul and the only Byzantine church in Istanbul that has not been converted into a mosque. Hagia Irene also holds a synthronon. Synthronons are rows of built benches that are arranged in a semicircle in the apse. During Divine Liturgy this is where the clergy would sit. This is the only synthronon that has survived in the city from the Byzantine era.