The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, colder neighbor.

(CNN) — Here’s a look at the exploration of Mars. The United States, Soviet Union and China are the only three countries to land a spacecraft on Mars. There have been nine successful US Mars landings: ...

NASA’s MAVEN spacecraft has confirmed, through nearly a decade of orbital observations, that solar wind physically strips gas from Mars’ upper atmosphere in a process called sputtering. That finding ...