NGC 5128 - Centaurus A

At a distance of 16,000 light years and a diameter of 150 light years, Centaurus A is the most massive globular cluster in the Milky Way. It is estimated to contain around 10 million stars and has a total mass of 4 million solar masses. The stars in the core of Omega Centauri are so crowded that they are estimated to average only 0.1 light years away from each other. It has been speculated that Omega Centauri is the core of a dwarf galaxy that was disrupted and absorbed by the Milky Way.