When Albert Reitz went out to mow his lawn, the last thing he expected was that the ground would cave beneath him. It turns out Albert and the rest of his neighbors were living on top of a sinkhole. Even more surprising was what the hole lead to underground. It was a day like any other in Blackhawk, South Dakota. Resident Albert Reitz was out mowing his lawn like he had so many times before.
Source
Arabic
French
Spanish
Portuguese
Deutsch
Turkish
Dutch
Italiano
Russian
Romaian
Portuguese (Brazil)
Greek