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.

Astronomy

The Geology and History of Liquid Water on Mars

Quick fact

The youngest known lake on Mars may have existed around 110,000 years ago, possibly formed by melting snow from a past ice age—evidence that liquid water can appear even in the Amazonian period.

Why this is interesting

Mars looks like a bone-dry desert today, yet its planet-wide valleys, deltas, and lakebeds reveal that rivers and lakes once carved this world. What happened to all that water?