There are more than 400 registered churches in Iran, out of which three churches and one pilgrimage ritual in East Azarbaijan and West Azarbaijan provinces have been inscribed on the List of World Heritage of the United Nations Educational, Scientific and Cultural Organization (UNESCO).
Saint Thaddeus Monastery in Chaldoran and Saint Mary Church in Maku, both in West Azarbaijan Province, and Monastery of Saint Stepanos in Julfa, East Azarbaijan Province, are three important tangible cultural monuments and among cultural and religious attractions of northwestern Iran.
Pilgrimage ritual of Saint Thaddeus Monastery was registered on UNESCO List in 2020. More than 5,000 Christians participate in the ritual, which is held in July each year.
It is worth mentioning that 17 intangible cultural heritages of Iran have been registered on the World List. An intangible cultural heritage is a practice, representation, expression, knowledge, or skill considered by UNESCO to be part of a place's cultural heritage.
Saint Thaddeus Monastery is located in Chaldoran county some 20 kilometers from Maku.
The annual three-day pilgrimage to St. Thaddeus Apostle Monastery in northwestern Iran
The commemoration ceremony includes special liturgies, processions, prayers and fasting. It culminates in a Holy Mass with Holy Communion.
The pilgrimage is the primary social and cultural event of the year; because attendees reside in tents in close proximity to one another, the sense of community is enhanced.
The monastery has been a pilgrimage site for over nineteen centuries. Some pilgrims from Armenia participate in the ritual. However, during the years of Soviet power in Armenia, participating in the pilgrimage was prohibited. Only after independence in the 1990s was the pilgrimage from Armenia resumed.
There are also important churches in Iranian provinces of Isfahan, Qazvin, Mazandaran, Tehran, and Khuzestan.