Mars is the fourth planet from the Sun in the Solar System. It is also the last planet in the
Inner Solar System. Mars is dry, rocky and cold. It is home to the
largest volcano in the Solar System. Mars is named after the
mythological Roman god of war because it is a red planet, which
signifies the colour of blood

The GAC (German Aerospace Centre) discovered that Earth lichens can survive in simulated Mars conditions. Possible that there are also pieces of the Earth on Mars.

Mars's moon Phobos appears about one
third the angular diameter of the full moon as it appears from Earth,
Deimos appears more or less star-like and appears only slightly brighter
than Venus does from Earth.

a dense, metallic core region overlaid by less dense materials

core region about 1,794 km ± 65 km (1,115 mi ± 40 mi) in radius

consisting primarily of iron and nickel with about 16–17% sulphur

Besides silicon and oxygen, the most abundant elements in the Martian
crust are iron, magnesium, aluminium, calcium, and potassium. The
average thickness of the planet's crust is about 50 km (31 mi), with a
maximum thickness of 125 km (78 mi).

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