Meet NGC 4911: a pretty little galaxy found about 320 million light-years from Earth in the constellation of Coma Berenices. From our far-away vantage point, this galaxy is seen face-on, with all of its features extremely clear thanks to Hubble's capacity to take long-exposure images.
This particular image has it all, the bright reservoir of superheated gas, the brilliant, reddish-brown dust lanes, the glorious 'halo' that encircles the galaxy like a pinwheel, and the numerous galaxies interacting with it gravitationally. In reality, the halo is actually an extremely large spiral arm that whips all the way around the galaxy's rim: a feature that wouldn't be viewable at all if it weren't for the long exposure.
We can't forget the pink glow of hydrogen clouds, which allude to star formation activity, specifically related to on-going gravitational encounters (of the first kind?) between NGC 4911 and other members of the Coma Cluster (which it, along with around 1,000 other galaxies, is a member of).
The Coma Cluster is currently the densest galaxy cluster in the local universe. Since they are all packed together so tightly, collisions, mergers and gravitational interactions are as common as they come. Therefore these galactic companions rarely remain untouched for very long.
Per NASA, this image is naturally-colored, and it combines a wealth of data taken by Hubble's Wide Field Planetary Camera 2 and the 'Advanced Camera For Surveys,' all taken throughout 2006, 2007 and 2009, for 28 hours of overall exposure time.
See a larger image here.