Okay kiddo, have you ever seen a really big ditch or crack in the ground? That's called a ravine! It's basically a big hole that's formed over a long, long time.
Sometimes, rivers or streams will run through ravines and make them even bigger. And since they're so deep, it can be pretty hard to climb out of them if you fall in.
But ravines can also be really pretty! Lots of plants and animals like to live in them because they're dark and cool. So next time you see a big crack in the ground, remember - that's a ravine!