The Hercules Cluster, also known as Abell 2151, is a large group of galaxies located in the constellation Hercules. It is one of the richest galaxy clusters known, containing over 100 galaxies, many of which are elliptical in shape. The cluster is approximately 500 million light-years away from Earth and spans about 2 million light-years across. The Hercules Cluster is notable for its high concentration of dark matter, which influences the motion of the galaxies within it. This cluster is also a site of significant astronomical research, helping scientists understand the formation and evolution of galaxies and the large-scale structure of the universe.