Giant stars are massive stars that have expanded and cooled after exhausting the hydrogen in their cores. They are significantly larger than the Sun, often having diameters up to 100 times greater. These stars are typically classified into two categories: red giants and blue giants, depending on their temperature and color. As they evolve, giant stars undergo various changes, including the fusion of heavier elements in their cores. Eventually, they may end their lives in spectacular explosions known as supernovae, leaving behind remnants such as neutron stars or black holes. Their life cycles contribute to the enrichment of the universe with heavier elements.