Oops

A cartoon cliche; find yourself stuck underwater on the bed of a lake, maybe chained to something? Simply pull out the plug and bingo, all the water disappears. Maybe it was something that influenced these engineers? What happens if we drill a little hole into the bed of a lake, above a massive salt mine? Hmmm..

Not to be confused with natural sinkholes, and nature's attempts to help Darwin Awards nominees; Would you stand here and carry on filming?

Or sit calmly in a boat when this is happening?

Nah, nor me.