HII Regions are areas in space where hydrogen gas is ionized, meaning the hydrogen atoms have lost their electrons. This ionization typically occurs near hot, young stars that emit high-energy ultraviolet light. The intense radiation from these stars energizes the surrounding hydrogen gas, creating a glowing region that can be observed in various wavelengths of light. These regions are often associated with star formation, as the presence of hot stars indicates that new stars are being born nearby. HII Regions can vary in size and brightness, and they play a crucial role in the evolution of galaxies by contributing to the chemical enrichment of the interstellar medium.