This is a fascinating simulation that shows how the Moon evolved from its original form—about 4.5 billion years ago—to what we can see today. It starts with the big impact that formed its South Pole's Aitken Basin, 4.3 billion years ago.
A few million years after the formation of the Aitken Basin, the Moon had a very rough time—just like our home planet. It went through a period of heavy meteor bombardment. That's when its main basin was formed. This violent era lasted from 4.1 to 3.8 billion years ago, but it wasn't the last one.
The Moon resisted stoically and deformed for a few more years, only to sustain a very long storm, with smaller asteroids constantly pounding her surface. This process, known asintermediate cratering, lasted more than two billion years. Then, about 1 billion years ago, new impacts created the ray craters—called that way because the material that was ejecting on impact, forming ray shapes around them. This process gave the final touch to the Moon's topography that we know today.
This video was made by scientists at NASA's Goddard Space Flight Center using data from the Lunar Reconnaissance Orbiter.