From Wikipedia: "Omega Centauri ( NGC 5139, or Caldwell 80) is a globular cluster in the constellation of Centaurus that was first identified as a non-stellar object by Edmond Halley in...
M4, a.k.a NGC 6121, is the closest globular cluster to our solar system ~7200 light-years away and 75 light-years across in Scorpius, estimated to be ~12.2 billion years old. Some whi...