What are stalagmites and stalactites? How are they formed?

In some limestone caves, sometimes conical pillar-like objects hanging from the roof of the caves and some rising from the floors are seen. These conical pillars which grow upward from the floor of the caves are known as stalagmites, and the structures which grow downwards from the roof are called stalactites.

These are formed by water dripping from the cracks in the rocks containing calcium hydrogen carbonate. Calcium hydrogen carbonate converts to calcium carbonate when pressure is released. Gradually, calcium carbonate deposits both on roof and floor to form stalagmites and stalactites.