I remeber an old grade school buddy...
His dad (or a previous owner of their house) had one built in the basement of their house...
It looked dark and spooky to me at the time...They used it to store junk. Our neighbors also had one in their back yard. It was always an item of curiosity when us kids were running around the neighboorhood looking for trouble to get into. We thought it would make a neat fort...Kind of like an underground tree house.
Scott