Mars is the fourth planet from the Sun. It’s called the Red Planet because the ground is red and dusty. Mars is smaller than Earth and very cold. The air there is not safe to breathe.

No people live on Mars, but scientists have sent robots to drive around and learn more about it. Mars has two small moons. A long time ago, it may have had water. Now it is dry with big mountains and deep valleys. In the future, people might visit Mars with spaceships.