Globular clusters are tightly packed groups of stars that orbit around galaxies. They can contain thousands to millions of stars, all held together by their mutual gravity. These clusters are typically very old, with some stars being over 10 billion years old, making them important for studying the early universe and the formation of galaxies like the Milky Way. These clusters are often found in the halo of galaxies and can be seen as bright, spherical collections of stars. Their dense star population can lead to interesting phenomena, such as interactions between stars and the formation of exotic objects like neutron stars and black holes.