Milky Way is chewing up two dwarf galaxies. UPDATE: Third collision coming up.

Scientists peered through the bright band of the Milky Way with the equivalent of night vision goggles. They found the two closest galaxies are tiny ones mostly inside our own and about 1% the size of ours. They have been crashing into us for some time and are getting stirred into the blazing mix.
1994   Sagittarius Dwarf found.
2003   Canis Major Dwarf found.

Philosopher Immanuel Kant is the first to have suggested the Milky Way might be a galaxy (1775).

UPDATE:   The Sagittarius Dwarf has messed with our galaxy twice in the last two billion years and is only ten million years away from striking the southern face of the Milky Way on the third pass through.  The dwarf is being stripped of its native material according to telescope data and detailed simulations.