Stalactites, stalagmites, and columns are formed over long periods of time by the slow deposit of material by dripping water. Stalactites hang from the ceiling, stalagmites grow from the ground, and columns are pillars where a stalactite and stalagmite have fused together.

In fictional worlds, stalactites may be at risk of falling and pose a terrain hazard to characters below. Stalagmites may act like jagged rocks and may be found at the bottom of a chasm. Columns may help support the roof of a cavern and their destruction may lead to total cavern collapse. Stalactites, stalagmites, and columns, if sufficiently large, may house underground cliffside settlements or cliffside pathways.