In Kyiv, mysterious underground passages were discovered during repair and restoration work on the grounds of the National Conservation Area St. Sophia of Kyiv. These passages are believed to lead to St. Sophia Cathedral, however, there is very little known about them in the historical record. (Photo: Vadym Kyrylenko).
Follow
@TheOldGuy It was not unusual for old cathedrals to have tunnels connecting with the nuns' housing or nunnery. This was so they could visit the cathedral without having any contact with the public.
Some orders required zero contact with outsiders, not even visual contact.
I'm not saying that's definitely the case here but I'll bet it is.
