 Here's a map of our local superclusters, including the Virgo supercluster. As you can see, galaxies and clusters of galaxies are not uniformly distributed in the universe. Instead, they collect into vast clusters, filaments and walls of galaxies. Interspersed with large voids in which very few galaxies seem to exist, a filament is constructed of galaxies and galaxy clusters. The Perseus-Pegasus filament is an example. Walls are much wider and thicker than filaments. Here we see the Fornax, Centaurus, Sculptor and the Great Wall, or Coma Wall. The Great Wall is one of the longest known superstructures in the universe. It is approximately 200 million light years away and measures over 500 million light years long, 300 million light years wide and 16 million light years thick. Voids are the vast empty spaces between filaments, which contain very few or no galaxies at all. There are 25 major voids in our local superclusters. Only a few are marked here. The Sculptor Void is the largest in the nearby universe. Let's take a look at some of the superclusters and some of the galaxies photographed by Hubble that are contained in these superclusters.