Good Evening;

This story from Poland has echoes of a similar situation in New York City with it's miles of underground tunnels, abandoned sub-sub basements, old subway stations, etc.........:

http://news.yahoo.com/homeless-underground-survive-deep-freeze-132921932.html

The few similar underground spaces in Baltimore are either patrolled, access blocked, susceptible to flooding and/or leakage, too well known as party spots, as yet undiscovered, or already claimed and occupied. 

But I'm always looking and snooping.

Later...........................Dave