Mercury

Mercury is a telluric planet of the solar system, the innermost and smallest (4879 km at its equator) of all eight planets known to orbit the Sun; accordingly, Mercury only takes 88 days to complete one revolution around our star.

The planet's surface is, just like Moon's, heavily covered with craters, as a result of it's lack of a real atmosphere and of an active geology that would periodically renew parts of the surface's aspect.