Viking 1 was the first spacecraft to successfully land on Mars, touching down on the surface on July 20, 1976.

Olympus Mons is a shield volcano on Mars and is the largest volcano in the Solar System, with a height of 21.9 kilometers (13.6 miles) and a diameter of 600 kilometers (373 miles).

Opportunity discovered evidence of past water activity on Mars, including ancient riverbeds and sedimentary rocks that formed in the presence of liquid water.

Phobos is the larger of the two moons of Mars, with a diameter of 22.2 kilometers (13.8 miles) and an orbital period of 7 hours 39 minutes.

Mariner 9 was the first spacecraft to orbit Mars, arriving in orbit on November 14, 1971.

The average temperature on Mars is -63°C (-81°F), with temperatures ranging from -125°C (-193°F) at the poles to 20°C (68°F) at the equator during the summer.

Curiosity discovered organic molecules on Mars, including methane and benzene, which are essential for life as we know it.

The Martian polar ice caps are composed of water ice and carbon dioxide ice. The North Polar Cap has a diameter of about 1,000 kilometers (621 miles) and a thickness of up to 3 kilometers (1.9 miles), while the South Polar Cap has a diameter of about 600 kilometers (373 miles) and a thickness of up to 1 kilometer (0.6 miles).

Phobos 2 was the first spacecraft to successfully land on the Martian moon Phobos, touching down on the surface on March 27, 1989.

Valles Marineris is a canyon system on Mars and is the largest canyon in the Solar System, stretching for over 4,000 kilometers (2,485 miles) and reaching a depth of up to 7 kilometers (4.3 miles).

Perseverance discovered evidence of ancient microbial life on Mars, including organic molecules and sedimentary rocks that formed in the presence of liquid water.

Dust devils are common on Mars and are caused by the heating of the Martian surface by the Sun. They can reach heights of up to 1 kilometer (0.6 miles) and can travel at speeds of up to 100 kilometers per hour (62 miles per hour).

No spacecraft has yet successfully landed on the Martian moon Deimos.

A Martian year, or sol, is the time it takes for Mars to complete one orbit around the Sun. It is equal to 687 Earth days.

Phobos 2 was the first spacecraft to successfully land on the Martian moon Phobos, touching down on the surface on March 27, 1989.