I recently saw a "Dateline"-type show about a girl who was kidnapped in the south somewhere, and taken to an underground hideout in the woods. It was hidden so well that searchers walked right over it and never knew it was there. She was kept there and raped daily. She decided to pretend she was happy to be there and gained some trust from the kidnapper. She began sending text messages from his phone while he was sleeping, but none of them got through until one night she was able to push the bunker top open and get a signal. She eventually got away, but of course I can't exactly remember how. I wish I could remember her name, it was a fascinating story with a good ending. But the point is, the underground thing is not unheard of.