The Mundo is a river in southeastern Spain that originates slightly south of Riópar in the mountain plateau Calar del Mundo and flows toward the town, then westward until joining the Segura south of Hellín.

The Arroyo de Tobarra is the only significant tributary in its lower course.

[4] The Mundo river is known for its picturesque source (Reventón del Rio Mundo), which is considered one of the world's most beautiful river sources.

It originates from a cave in the middle of a tall cliff and forms a waterfall with a height of almost 100 meters.

Subsequently, it forms a series of smaller cascades and pools.