Aren't black holes at the center of all the galaxies that we know about?
If that is true, picture this:

Planets, which may or may not be able to support life, revolve around suns.
Suns, which may or may not have planets around them, revolve around black holes.

What do black holes revolve around?

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All activities should be looked at as merely being like a dream, a phantom, a bubble, a shadow, a drop of dew or a flash of lightning.

-The Diamond Sutra (opening line)