NGC 3521 is a flocculent spiral
galaxy that is located approximately 35 million light years away
in the constellation of Leo, the lion. It was discovered by William
Herschel in 1784.
The galaxy has a whispy shell, lending
to its common name: The Bubble Galaxy. This shell is likely the
tidal debris resulting from long-past mergers with other galaxies.
This has caused the galaxy to lose its characteristic spiral arms
and create numerous star-forming regions.