To say that the newly discovered Phoenix Cluster of galaxies is "big" would be an understatement. In its entirety, the Phoenix Cluster is estimated to weigh twenty-five hundred thousand million times more than our sun, with a black hole at the center that's eating a sun a week, and Phoenix is pumping out baby stars like nobody's business.
Most galactic clusters aren't ideal places for birthing new stars. The massive central black holes that keep them together tend to release so much energy that gas is prevented from cooling off enough to collapse into a shiny new baby star. In the Phoenix Cluster, however, its black hole is too busy eating to send out the huge shockwaves that would otherwise keep the cluster's gas energized, leading to a rate of star formation that's the highest ever observed for the middle of a galaxy cluster: 700 new stars per year. That's about 698 more per year than we get here in the boring ol' Milky Way.
Eventually, in about a hundred million years or so, the black hole at the center of the Phoenix Cluster is going to get too big for its own good, and it'll start releasing shockwaves that will pump enough energy into the cluster to put a damper on all of this star formation. Of course, by that time, the central galaxy will have grown into one of the largest galaxies in the known universe. Meanwhile, we'll be using the data that we're getting from this "extreme" region of space to make other regions of space feel bad for being not nearly as interesting.