Hypercluster

A galaxy filament, also known as A galaxy wall or a supercluster complex or a hypercluster, is a cosmological structure. Filaments consist of gravitationally-bound galaxies; parts where a large number of galaxies are very close to each other are called superclusters. Discoveries about "hyperclusters" (clusters of superclusters) started in the 1980s.

Formation
In the standard model of the evolution of the universe, galactic filaments form along and follow web-like strings of dark matter. It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts baryonic matter, and it is this "normal" matter that astronomers see forming long, thin walls of super-galactic clusters.