A sinkhole is a depression or hole in the ground caused by the collapse of a surface layer. They often form in areas where the underlying rock, such as limestone, is dissolved by water, creating underground cavities. When the ground above can no longer support its weight, it collapses, resulting in a sinkhole. Sinkholes can vary in size, from a few feet to hundreds of feet across, and can occur suddenly or develop over time. They are commonly found in regions known as karst landscapes, where the geology is prone to such formations. Sinkholes can pose risks to buildings, roads, and other infrastructure.