Follow your curiosity

What discovery has been shared with you?

FACTREE gives you something interesting to discover every day — and something worth talking about together.

Start with one fact. Explore it, go deeper, then follow whichever branch catches your imagination.

Choose subjects for a surprise

Exploring any topic

Begin your discovery

Your next discovery is one click away.

Choose one or more subjects above, or leave Any Topic selected and let curiosity decide.

Geography

How Canyons Are Formed Through River Erosion Over Millennia

Quick fact

The Grand Canyon in Arizona is over 277 miles long, up to 18 miles wide, and reaches a depth of over a mile, all carved by the Colorado River over about 5 to 6 million years.

Why this is interesting

Think of a river as a slow-moving knife, slicing through solid rock over millions of years. How does water—something so soft—carve the world's most dramatic canyons?