It is no longer the case that the Milky Way is “one of a kind”. The first groups of galaxies resembling the Milky Way and its companion galaxies, the Magellanic Clouds, have been discovered.
Hundreds of thousands of galaxies were surveyed in the most detailed map of the local universe yet, and not one but two exact matches for the Milky Way and its surrounds were located.
The discovery of these twin galaxies is extremely rare given that only 3% of galaxies similar to the Milky Way had companion galaxies like the Large and Small Magellanic Clouds, which are not only rare but possibly short lived occurrences.
Read more at The University of Western Australia