Moon

Small, much smaller than the Earth (the diameter is one-fourth as large), but large for a satellite

Dense core, lighter crust

Very little atmosphere

Heavy cratering

Previous history of volcanic eruptions

Is (or was) there liquid water?

Why are the maria (flat plains) predominantly on the near side?

Image of the Moon, with a mottled yellow and dark cratered surface. Astronaut wearing a space suit and standing on the surface of the Moon. The rocky ground shows small craters, and the astronaut's dark, sharp shadow extends over a large distance. The space suit is white (to reflect light), and in the shiny face plate one can see reflected another astronaut taking the photograph. The Earth and the Moon are shown together in a single image, with both bodies having a dark left side and a lit up right side due to the Sun's position far away to the left.
A lunar rover vehicle, designed to seat two astronauts and travel over the surface of the Moon. It resembles a dune buggy, with large tires and an open construction. An igneous rock sample brought from the Moon back to Earth. The black and white photograph shows a roughly spherical rock, with many sharp angles and irregular shaping.
Images of the Terran Moon, and our exploration of the surface. [NASA]