Rank #21
The Milky Way is estimated to contain between 10 and 20 billion black holes.
This description provides an overview of the estimated number of black holes that exist within the Milky Way galaxy. It is believed that the Milky Way contains between 10 and 20 billion black holes, making it one of the most densely populated galaxies in the universe. This number is constantly being revised as new discoveries
From Wikipedia
The Milky Way or Milky Way Galaxy, or simply the Galaxy, is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye.