Stalactites grow down from the ceiling of a cavern, not up from the floor. They are formed by the slow dripping of mineral-rich water. As the water drips, it leaves behind a deposit of minerals like calcium carbonate. Over time, these deposits build up and form the elongated, icicle-like structures we know as stalactites.

Stalagmites, on the other hand, do grow up from the floor of a cavern. They are formed by the same mineral-rich water, but this time, the water drips onto the floor. As the water splashes and evaporates, it leaves behind mineral deposits that build up and form the cone-shaped stalagmites.

So, to summarize:

* Stalactites: Grow down from the ceiling.

* Stalagmites: Grow up from the floor.