Messier 45 (M45), commonly known as the Pleiades, is a bright and prominent open star cluster located in the constellation Taurus, approximately 440 light-years from Earth. Composed of several hundred young, hot blue stars formed within the last 100 million years, the cluster is easily visible to the naked eye and has been recognized since antiquity. Surrounding the stars is a delicate web of blue reflection nebulosity, created as starlight scatters off interstellar dust that the cluster is currently passing through rather than material from which it formed. The Pleiades serve as a classic example of a young stellar population and offer an important benchmark for studying stellar evolution, cluster dynamics, and the interaction between stars and the interstellar medium.