Features
    Craters
        Was thought to be cause by volcano
            Actually, caused by impacts of meteoroids
    Highlands
    Maria
        Sea
            Actually, low dry areas – flooded by molten material

Collision Theory
    4.5 billion years ago
    Collision on a young earth
    Material from Earth broke off
    Material thrown into a orbit
    Forms the moon

http://www.space.com/scienceastronomy/top_10_cool_moon_facts-10.html