Mars is the fourth planet from the Sun – a dusty, cold, desert world with a very thin atmosphere. Mars is also a dynamic planet with seasons, polar ice caps, canyons, extinct volcanoes, and evidence that it was even more active in the past.

Mars is one of the most explored bodies in our solar system, and it's the only planet where we've sent rovers to roam the alien landscape.

Source NASA

Deimos & phobos

Asaph Hall was about to give up his frustrating search for a Martian moon one August night in 1877, but his wife Angelina urged him on. He discovered Deimos the next night, and Phobos six nights after that. Ninety-four years later, NASA's Mariner 9 spacecraft got a much better look at the two moons from its orbit around Mars. The dominant feature on Phobos, it found, was a crater six miles (10 kilometers) wide – nearly half the width of the moon itself. It was given Angelina's maiden name: Stickney.

Source NASA