A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the earth's surface caused by karst processes - the chemical dissolution of carbonate rocks[1] or suffosion processes[2] f.e. in sandstone. Sinkholes may vary in size from less than 1 to 600 meters (3.3 to 2,000 ft) both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. They may be formed gradually or suddenly, and are found worldwide. These terms are often used interchangeably, though many distinguish between features a surface stream flows into and features with no such input. Only the former are described as sinks, swallow holes or swallets.
--Wikipedia
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