In addition to ground part of the original architectural monuments there is also a catacomb in Lutsk. This is old quite wide network of underground tunnels in the Old Town.

The entrance of the catacombs is situated near the Saints Peter and Paul Cathedral.
There is a belief that catacombs are the continuation of the Cathedral. In the cave there were found bricks with "1554"and "1654", which indicates a possible age of catacombs. Eyewitnesses say that one of the underground passages connected the Cathedral with the Lubart Castle but in the 60's of XX century that pass was ruined.