Underground Church in the New Jerusalem Monastery

In the New Jerusalem Monastery on Istra, there is the Underground Church of Saints Constantine and Helena (in Jerusalem, a similar church was carved into the rock).
The church, from the east, adjoins the Resurrection Cathedral of the monastery and is connected to the cathedral by a passage from the altar part. The construction of the church began under Nikon, in 1658. The walls of the church rose 1.5 meters above ground level; it was crowned with one chapter, decorated with tiles. In the middle of the 18th century, a moat was dug to protect the building from groundwater, which was 6 meters deep in the ground. At the beginning of the 19th century, a tunnel was built through which water was diverted, and the moat itself was lined with white stone. The interior of the church was redesigned in the Baroque style in the middle of the 18th century.
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