Galactic Center
The Galactic Center is the rotational center of the Milky Way galaxy, located approximately 25,000 light-years from Earth in the direction of the constellation Sagittarius. It is a densely populated region containing a supermassive black hole known as Sagittarius A*, surrounded by a high concentration of stars, gas, and dust.
Source: nasa.gov
APODs including "Galactic Center"
Sagittarius Dwarf to Collide with Milky Way
16/02/1998
Our Galaxy is being invaded. Recent observations indicate that in the next 100 million years, the Sagittarius Dwarf galaxy will move though the disk of our own Milky Way Galaxy yet again . The Sagittarius Dwarf (Sgr), shown as the extended irregular shape below the Galactic Center, is the closest of 9 known small dwarf spheroidal galaxies that orbit our Galaxy. Don't worry, our Galaxy is not in danger, but no such assurances are issued for the Sagittarius Dwarf: the intense gravitational tidal forces might pull it apart. Oddly, however, Sgr's orbit indicates that is has been through our Galaxy several times before, and survived! One possibility is that Sgr contains a great deal of low-density dark matter that hold it together gravitationally during these collisions.