 The Perseus Pisces supercluster is a long, dense wall of galaxies with a length of almost 300 million light-years that is around 250 million light-years away. It is one of the largest known structures in the universe. This plot of the brightest galaxies in the supercluster show how prominent it is. At the left end of the supercluster is the massive Perseus cluster, one of the most massive clusters of galaxies within 500 million light-years.