In 1835, a laborer in Kent, England, was doing his usual field work. What wasn’t so usual was when he struck the soil with his spade and it just disappeared into the Earth. Apparently, he was standing on something hollow, but from the surface, he could see nothing.
Word spread, and a local schoolteacher soon volunteered his young son, Joshua, to be lowered into the hole with a candle. If you think dipping your child into a mysterious cavern in the Earth seems a bit, well, unsafe, we do, too.