Thanks for taking on such a broad and intense subject.

I was fascinated recently when a TV show I happened upon (the name was something like Hidden Spaces) took a tour of a home in Ohio that had been a station on the UGRR. The home was full of false walls and floors and other common looking household items that could be used to help hide people for days at a time if necessary.

Any idea how many homes like this are still in existence? Are they concentrated in a specific geographical area?