It's possible you're thinking about:
* The Moon's Formation: The current theory is that the Moon formed from the debris of a massive collision between Earth and a Mars-sized object early in our solar system's history. So, in a way, the Moon was "broken apart" in that collision, and then reassembled from the resulting debris.
* The Lunar Maria: The dark, flat plains on the Moon's surface called "maria" (Latin for "seas") are actually giant impact craters filled with solidified lava. They were "broken apart" by asteroid impacts and then "reformed" by volcanic activity.
Let me know if you were thinking of something else!
