Though covered with reeds and sedge, the small field turned out to be a deep sinkhole of waterlogged clay and silt.

The 110 feet diameter and 200 feet deep sinkhole dumped this toxine into subterranean caves that lead to the Florida Aquifer.

Like the nearby Red Lake, it lies in a deep sinkhole possibly formed by the collapse of an enormous underground cave.

The Bradley had been crossing shallow ground water and dropped into a deep sinkhole that was not visible on the surface.

So it was in 1994, when one of these stacks collapsed into a 150-foot (46-meter) deep sinkhole.

In Guatemala City, a sinkhole 30 stories deep collapsed, killing 15 people and placing a further 300 residents in danger.

The cave entrance is at the bottom of an 18 m deep sinkhole.

She was afraid there might be an abrupt drop-off or a really deep sinkhole somewhere in the meadow.

Early in the morning on Feb. 23, 2007, a 330-foot (101-meter) deep sinkhole appeared almost instantly, killing at least three people and devouring homes in a packed urban area.

The name derives from a local geological feature, a type of deep karst sinkhole called a foiba.