1. Dura-Europos church
The Dura-Europos church is the earliest identified Christian house church. It is located in Dura-Europos in Syria and dates from 235 AD. The site of Dura-Europos, a former city and walled fortification, was excavated largely in the 1920s and 1930s by French and American teams. Within the archaeological site, the house church is located by the 17th tower and preserved by the same defensive fill that saved the nearby Dura-Europos synagogue (Wikipedia).
The designation of the oldest church in the world requires careful use of definitions, and must be divided into two parts, the oldest in the sense of oldest surviving building, and the oldest in the sense of oldest Christian church congregation. Even here, there is the distinction between old church buildings that have been in continuous use as churches, and those that have been converted to other purposes; and between buildings that have been in continuous use as churches and those that were shuttered for many decades. In terms of congregations, they are distinguished between early established congregations that have been in continuous existence, and early congregations that ceased to exist (Wikipedia).
2. Megiddo church
Megiddo church in Tel Megiddo, Israel is one of the oldest church buildings ever discovered by archaeologists, dating to the 3rd century AD. In 2005, Israeli archaeologist Yotam Tepper of Tel-Aviv University discovered the remains of a church, believed to be from the third century, a time when Christians were still persecuted by the Roman Empire. The remains were found at the Megiddo Prison, which is located a few hundred meters south of the Tel. Among the finds is an approx. 54-square-metre (580 sq ft) large mosaic with a Greek inscription stating that the church is consecrated to “the God Jesus Christ.” The mosaic is very well preserved and features geometrical figures and images of fish, an early Christian symbol (Wikipedia).
3. Monastery of Saint Anthony
The Monastery of Saint Anthony is a Coptic Orthodox monastery standing in an oasis in the Eastern Desert of Egypt. Hidden deep in the Red Sea mountains, it is located 334 km (207 miles) southeast of Cairo. It is one of the oldest monasteries in the world, and was established by the followers of Saint Anthony, who is considered to be the first ascetic monk. The Monastery of St. Anthony is one of the most prominent monasteries in Egypt and has strongly influenced the formation of several Coptic institutions, and has promoted monasticism in general. Several patriarchs have been pulled from the monastery, and several hundred pilgrims visit it each day (Wikipedia).
4. Saint-Pierre-aux-Nonnains basilica
Saint-Pierre-aux-Nonnains basilica is a historic church building in Metz, France that was built in 380 AD and is one of the oldest churches in Europe. The building was originally built to be part of a Roman spa complex, but the structure was converted into use as a church in the 7th century becoming the chapel of Benedictine monastery. A new nave was constructed in the 1000s with further interior renovations. In the 16th century the building became a warehouse and remained so until the 1970s when it was restored and opened for concerts and exhibitions (Wikipedia).
5. Church of Our Lady Mary of Zion
Church of Our Lady Mary of Zion of the Ethiopian Orthodox Church is the most important church in Ethiopia. The original church is believed to have been built during the reign of Ezana, the first Christian emperor of Ethiopia, during the 4th century AD, and has been rebuilt several times since then. The church is in the town of Axum in the Tigray Province. Its first putative destruction occurred at the hands of Queen Gudit during the 10th century. Its second, confirmed, destruction occurred in the 16th century at the hands of Ahmad ibn Ibrihim al-Ghazi, after which it was rebuilt by the Emperor Gelawdewos, then further rebuilt and enlarged by Fasilides during the 17th century (Wikipedia).
6. Cathedral of Trier
Cathedral of Trier is a church in Trier, Rhineland-Palatinate, Germany. It is the oldest cathedral in the country. The edifice is notable for its extremely long life span under multiple different eras each contributing some elements to its design, including the center of the main chapel being made of Roman brick laid under the direction of Saint Helen, resulting in a cathedral added on to gradually rather than rebuilt in different eras. Its dimensions, 112.5 by 41 m, make it the largest church structure in Trier. Since 1986 it has been on the UNESCO list of World Heritage Sites (Wikipedia).
7. Church of Saint Simeon Stylites
The Church of Saint Simeon Stylites is a well preserved church that dates back to the 5th century, located about 30 km northwest of Aleppo, Syria. It is built on the site of the pillar of St. Simeon Stylites, a famed hermit monk. It is popularly known as Qalat Seman the ‘Fortress of Simeon’ (Wikipedia).
8. Hagia Sophia
Hagia Sophia is a former Orthodox patriarchal basilica, later a mosque, and now a museum in Istanbul, Turkey. From the date of its dedication in 360 until 1453, it served as the cathedral of Constantinople, except between 1204 and 1261, when it was converted to a Roman Catholic cathedral under the Latin Patriarch of Constantinople of the Western Crusader established Latin Empire. The building was a mosque from 29 May 1453 until 1934, when it was secularized. It was opened as a museum on 1 February 1935 (Wikipedia).
9. Saint Catherine’s Monastery, Mount Sinai
Saint Catherine’s Monastery, Mount Sinaiies on the Sinai Peninsula, at the mouth of a gorge at the foot of Mount Sinai in Saint Katherine city in Egypt. The monastery is Orthodox and is a UNESCO World Heritage Site. According to the UNESCO report (60100 ha / Ref: 954), this monastery is one of the oldest working Christian monasteries in the world together with the Monastery of Saint Anthony, situated across the Red Sea in the desert south of Cairo, also lays claim to that title (Wikipedia).
10. Church of the Nativity
The Church of the Nativity in Bethlehem is one of the oldest continuously operating churches in the world. The structure is built over the cave that tradition marks as the birthplace of Jesus of Nazareth, and thus it is considered sacred by Christians. The site is also revered by followers of Islam (Wikipedia).