Evidence supporting the existence of galaxy clusters and superclusters has been amassed over time. The surveys made by the Herschels in the eighteenth and nineteenth centuries, as well as observations made in the 1930s by astronomers such as Harlow Shapley of Harvard and Fritz Zwicky of Mount Wilson, strongly suggested the existence of superclusters.
In the 1950s, in the course of cataloguing clusters of galaxies from the photographic sky survey made with the 48 inch telescope at Palomar Observatory, George Abell discovered a number of clusters that were themselves collected into larger groups. Around the same time, Gerard de Vaucouleurs com- piled evidence that our Local Group was part of a Local
