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How do caves form?

A cave with a lake inside itCaves are formed when water, flowing below ground, hollows out the rocks. You may also come across caves at the seashore, where waves crash against the cliffs. Limestone caves are often made up of a series of chambers, linked by tunnels and shafts. Some have streams running through them, or lakes.


Diagram of a limestone cave system

Limestone caves

Limestone may look like solid rock, but it contains millions of tiny cracks. Rainwater seeps into these cracks. Over many years, the water dissolves the rock, widening the cracks and eventually forming caves.

A good way to remember the difference between stalactites and stalagmites is that stalaCtites form on the Ceiling, while stalaGmites grow up from the Ground.

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