To get back to the expressed topic of this good thread after all this thread creep:

It is a sad story from my youth that I was told about. My uncle got very tired of having to clean out the bottom of his too shallow outhouse. He lived in a cabin on old mining property in Southern Illinois, so he built his next outhouse over an abandoned mine shaft that he'd never ever have to dig out.

The day he finished it, he went out there to be the first one to use it! After 4 hours, my father decided they ought to go and check on his wellbeing. They found him sitting there----dead----aparently asphyxiated. My dad figured out, he thought, what had "gone down"---so to speak. For some reason, uncle always held his breath until he heard the splash!!!!!

Art Thieme