This was my first time entering and you will see how quicly I got out :D 
Built around 1400 AD for the family of local nobility, this two-level crypt is small and roughly hewn but artfully half-lit and notable for the boldly sculpted cross, sun and crescent moon motifs (downstairs), a rare surviving memorial to the independent Bosnian Church.
Catacombs (underground church, the crypt) in the Jajce is located inside of city walls. Between the late 14th th and early 15th-century, when the town experienced a remarkable political and cultural development, the mighty bosnian duke Hrvoje Vukcic - Hrvatinić gave the order to build catacombs as a place of his last residence and last place of residence Hrvatinića ducal family. 

Catacombs (underground church, the crypt) is an underground building carved into the solid rock and is placed 6m under the earth. 

Under the decision of the Commission for National Monuments Protection of BiH, the monument is since 2003 proclaimed as national monument of Bosnia and Herzegovina.
Comment below to support the creator!