Nicea was an ancient and medieval city in Asia Minor on the site of the modern Turkish city ​​of Iznik.

The city was located on the shore of Lake Ascania, and from land it was bounded by high hills, which created the best conditions for the defense of the city during the siege.

Derinkuyu, Cappadocia. Orthodox Church of Saint Theodoros Trion (Uzumlu Church) built in 1858 in Central Anatolia, Turkey

The Church of St. Pierre, located at the foothills of Mt Pilgrimage (Hac Dağı) in Hatay province is one of the most significant centers of Christianity. The cave known as the location where St. Peter had given his first sermon was upgraded and turned into a church after the Romans had adopted Christianity. The church was a harbor to the first Christians and the first pope, St. Peter, and contributed to the spread of Christianity in the world.

St. Mary Church is a Syriac Orthodox church in Diyarbakir. It is under the jurisdiction of the Syriac Archdiocese of Mardin, headed by Metropolitan Mor Filüksinos Saliba Özmen.The church was first constructed as a pagan temple in the 1st century BC, and the current construction dates back to the 3rd century. The church has been restored many times, and is still in use as a place of worship today.

Dayro d-Mor Gabriel  also known as Deyrulumur, is the oldest surviving Syriac Orthodox monastery in the world. It is located on the Tur Abdin plateau near Midyat in the Mardin Province in southeastern Turkey It has been involved in a dispute with the Turkish government that threatened its existence.

Now only a museum, once a Pagan temple, converted to first Church by Constantine the Great, later restored in the 6th century by Justinian I as the largest basilica in the Christian world. The building is a great architectural beauty and an important monument both for Byzantine and for Ottoman Empires. Once a church, later a mosque, and now a museum at the Turkish Republic, Hagia Sophia has always been the valuable of its time.This church was rebuilt three times on the
same place.

An important place of pilgrimage for Christians. It is located in what is thought to be the courtyard of St. Paul’s house
in the Kizilmurat quarter close to the Cumhuriyet Meydani (lit. Republic Square). The water level never drops and the water
is believed to be sacred with healing properties.

Currently, there are two active churches belonging to the Bulgarian Orthodox Church in Edirne. In addition to the better-known church of Saints Constantine and Helena, there is a smaller church of Saint George (bg. Свети Георги – Sveti Georgi, tr. Ayayorgi Kilisesi) in the city, built in the second half of the 19th century. It was formally consecrated on the 9th of May, 1880. The construction of the church was realised with the permission of Sultan Abdul Hamid II by the governor of Edirne, Rauf Pasha.

The Church of St. George  is the principal Eastern Orthodox cathedral located in Istanbul, the largest city in Turkey and, as Constantinople, capital of the Byzantine Empire until 1453. Since about 1600,it has been the seat of the Ecumenical Patriarchate of Constantinople whose leader is regarded as the primus inter pares (first among equals) in the Eastern Orthodox Church, and as the spiritual leader of 300 million Orthodox Christians worldwide

Hagia Irene or Hagia Eirene , sometimes known also as Saint Irene, is an Eastern Orthodox church located in the outer courtyard of Topkapı Palace in Istanbul. It is one of the few churches in Istanbul that has not been converted into a mosque, as it was used as an arsenal for storing weapons until the 19th century.The Hagia Irene today operates as a museum and concert hall.

“Chora Museum” (Kariye Müzesi) is a church building that constitutes the center of the Chora Monastery, which was a great building complex in the Eastern Roman Empire period, and it was dedicated to Jesus Christ. Since it stood outside of the
city walls built by Constantine, the building was called “Chora”, which means “in the country” or “outside of the city” in Greek.

Pammakaristos Church, also known as the Church of Theotokos Pammakaristos , is one of the most famous Greek Orthodox Byzantine churches in Istanbul, Turkey. Adapted in 1591 into the Fethiye Mosque, it is today partly a museum, the parekklesion. The edifice serves as one of the most important examples of Constantinople‘s Palaiologan architecture, and the last pre-Ottoman building to house the Ecumenical Patriarchate. It also has the largest amount of Byzantine mosaics in Istanbul after the Hagia Sophia and Chora Church.

It’s located on Büyükada, the largest of the Princes’ Islands. It’s a peaceful place at the top of the highest hill on the island. It isn’t usually a priority for tourists, but it’s a unique place to visit.

At the very top is the small Greek Orthodox Church of St. George. There has been a monastery on the same spot since 963, when the Byzantines ruled the city. A sign in front of the door reminds visitors to dress appropriately and be silent.

Bulgarian St Stephen Church , also known as the Bulgarian Iron Church, is a Bulgarian Orthodox church in Balat, Istanbul, Turkey. It is famous for being made of prefabricated cast iron elements in the neo-Byzantine style. The church belongs to the Bulgarian minority in the city.

The Cathedral of the Holy Cross  on Akdamar (Aghtamar) Island, in Lake Van in eastern Turkey, is a medieval Armenian Apostolic cathedral, built as a palatine church for the kings of Vaspurakan and later serving as the seat of the Catholicosate of Aghtamar.

Sumela Monastery is a Greek Orthodox monastery dedicated to the Virgin Mary located at Karadağ  within the Pontic Mountains, in the Maçka district of Trabzon Province in modern Turkey.

Nestled in a steep cliff at an altitude of about 1,200 metres (3,900 ft) facing the Altındere valley, it is a site of great historical and cultural significance, as well as a major tourist attraction within Altındere National Park. Due to an increase in rock falls, on 22 September 2015 the monastery was closed to the public for safety reasons for the duration of one year to resolve the problem; this was later extended to three years. It reopened to tourists 25 May 2019. The Monastery is one of the most important historic and touristic venues in Trabzon

Hagia Sophia  is a formerly Greek Orthodox church which was converted into a mosque in 1584, and located in Trabzon, in the north-eastern part of Turkey. It was converted into a museum in 1964 and back into a mosque in 2013. It dates back to the thirteenth century when Trabzon was the capital of the Empire of Trebizond. It is located near the seashore and two miles west of the medieval town’s limits. It is one of a few dozen Byzantine sites extant in the area. It has been described as being “regarded as one of the finest examples of Byzantine architecture.”

Virgin Mary House. Virgin Mary and Saint John escpaed from Jaruselam and they came to Ephesus. It is belived that Virgin mary stayed at this house.

The church in Antalya’s Demre district is known as the birthplace of St. Nicholas, better known as Santa Claus.

Alahan Monastery  is a complex of fifth century buildings located in the mountains of Isauria in southern Asia Minor (Mersin province in modern day Turkey). Located at an altitude of 4,000 ft, it stands 3,000 ft over the Calycadnus valley and is a one-hour walking distance from the village of Geçimli. Although termed a monastery in many sources, this attribution is contested and more recent scholarship consider it to be a pilgrimage shrine. The complex played a significant role in the development of early Byzantine architecture, and practically everything known about it can be attributed to the excavations of Michael Gough.

Served as a monument museum today, the Church of St. Paul is located in the Ulu Cami quarter. The church dedicated to St. Paul was originally built in the 11 th and 12th centuries A.D. and underwent major renovation in 1862. There are frescoes depicting Christ and the Four Evangelists with Angels on the roof. The church is an important place of pilgrimage
for Christians and in 1992-93 it hosted the “Saint Paul Symposium and Ceremony” organised by the Vatican.

Saint John Basilica and tomb. Saint John lived in a Ephesus later he was exciled to Patmos Island and later he came back to Ephesus and died here.for Christians and in 1992-93 it hosted the “Saint Paul Symposium and Ceremony” organised by the Vatican.

Dayro d-Mor Hananyo is an important Syriac Orthodox monastery. The monastery is located in the Syriac cultural region known as Tur Abdin, and is located three kilometers south east of Mardin, Turkey.

It is usually better known by its nickname, the “Saffron Monastery”  which is derived from the warm color of its stone.

According to the local Syriac community, the 6th-century church was originally established by the three Kings of the Orient. The Syriac name of the church is Yoldath (Aloho). The exterior of the dome and bell tower are 20th-century additions.

The church bears a striking similarity to the large church at the Deyr-ül Zafaran Monastery, and is considered the most beautiful example of church architecture in Tur Abdin.