The Moon

The Moon, also known as "Luna" in Latin and Spanish, is the 5th largest moon in the Solar System and the only natural satellite of Earth.

Characteristics
The Lunar surface is sometimes divided into two sections. The front of the Moon is the only side of it seen in the night sky, due to the moon being tidally locked. The front side has visible cooled lava oceans. The back side is scattered with craters.

Core
The Lunar core is hot, unlike the cores of most moons. It's also possible that the moon used to have a magnetic field, but it got destroyed during The Late Heavy Bombardment.