St. Jacob's Church is a fortified church dating back to the 13th century. The church is one of the oldest buildings on Saaremaa Island.
The church of Karja was built in the fourth quarter of the 13th or early 14th century by masters from Ojamaa (Gotland). Even before the construction of the stone church, already in 1254, there was a wooden church in Karja. Until 1896 the clergy was composed of Baltic Germans. The first Estonian clergyman was Karl Wöhrmann in 1896-1926.
The Peter and Paul Church in Kaarma was probably built in 1261. The high bell tower, whose east side rests on the west side, was completed in the 15th century. The eastern wall of the choir hall is illustrated by a rare triple window in Estonia. The interior of the church contains real treasures. Besides the 13th century paintings on the north wall of the choir. There are also 13th-century baptismal fonts as well as a wooden sculpture of Simon of Cyrene (mid 15th century) and an altar donated in 1547.