A sinkhole is a hole in the ground that forms when the surface layer suddenly collapses. Most sink occur i areas wh the ro below t surface i limestone o another ro that slo dissolves i water. Over thousands of years, slightly acidic rainwater seeps into cracks and gradually creates underground spaces. As long as the soil above is supported, nothing seems to change. When the support finally fails, the ground can collapse without warning, sometimes swallowing roads, cars, or even buildings. Human activities, such as pumping out too much groundwater, can make sinkholes more likely.

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