A globular star cluster is a spherical collection of stars that are tightly bound by gravity. These clusters typically contain thousands to millions of stars, all of which are generally old and have similar ages. They are found in the halos of galaxies, including our own Milky Way, and can be observed as bright, concentrated groups in the night sky. Globular clusters are important for studying the formation and evolution of galaxies. They provide insights into the early universe, as many of their stars formed over 10 billion years ago. Notable examples include M13 in the Hercules constellation and Omega Centauri, the largest known globular cluster.