A painting exhibition is currently under way at the Armenian St. Thaddeus Monastery in Iran on the occasion of the 12th anniversary of the monastery’s inscription on UNESCO World Heritage list, Tehran Times reports.

The exhibition, which displays 77 paintings by children and teenagers, was inaugurated by Archbishop Gregor Chiftechian, director of Iran’s Armenian monastic ensembles Sherly Avedian said.

Also known as the Qareh Klise (“the Black Church”), the monastery is one of the oldest surviving Christian monuments in the country. It is situated in Chaldoran county, some 20 kilometers from Maku, adjacent to the borders of Armenia, Azerbaijan, and Turkey.

The ancient church shows off elaborate bas-reliefs of flowers, animals, and human figures on its facade and exterior walls. It bears verses of the Old and New Testament in Armenian calligraphy as well.

St. Thaddeus Monastery hosts an annual religious ritual every summer. Last July, it hosted over 3,000 Christian worshippers coming together from Iran, Armenia, Syria, Lebanon, the Netherlands, France, Austria, Germany, Canada, and other countries.

Baptism of children and youngsters along with performances of traditional songs and dances are among highlights of the pilgrimage.

The festivity is of high importance for Iranian-Armenians who mostly come from the cities of Tabriz, Urmia, Tehran, Isfahan, and Qazvin, to stage the reunion in groups and families.

Attendees commemorate the martyrdom of St. Thaddeus, one of the twelve disciples killed while he was preaching the Gospel. The legend says a church dedicated to him was first built in 68 CE where Qareh Klise is standing.

Thaddeus was an apostle of Christ and the ceremony is rooted in the last supper with Jesus Christ on the night of his arrest and execution by the Roman soldiers.

Together with St. Stepanos Monastery and the Chapel of Dzordzor, Qareh Klise was placed on the UNESCO World Heritage list in 2008 under the name “Armenian Monastic Ensembles of Iran”.