Stalactite

A stalactite (from the Greek stalasso, (σταλάσσω), "to drip", and meaning "that which drips") is a type of formation that hangs from the ceiling of caves, hot springs, or manmade structures such as bridges and mines. Any material which is soluble, can be deposited as a colloid, or is in suspension, or is capable of being melted, may form a stalactite. The corresponding formation on the floor of the cave is known as a stalagmite.