HII regions are large clouds of gas and dust in space, primarily composed of hydrogen that is ionized by the intense ultraviolet radiation from nearby hot stars. These regions are often found in areas of active star formation, where new stars are born from the surrounding material. The ionization process causes the gas to glow, making HII regions visible in various wavelengths of light. These regions play a crucial role in the evolution of galaxies by contributing to the chemical enrichment of the interstellar medium. As stars within HII regions age and die, they release heavier elements back into space, which can later form new stars and planets, continuing the cycle of cosmic evolution.