Galaxy superclusters are massive groups of galaxies that are bound together by gravity. They can contain hundreds or even thousands of galaxies, along with gas and dark matter. Superclusters are among the largest known structures in the universe, and they can span hundreds of millions of light-years across. One of the most well-known superclusters is the Laniakea Supercluster, which includes our own Milky Way Galaxy. Superclusters are often found at the intersections of cosmic filaments, which are vast, thread-like structures made up of galaxies and dark matter. Understanding superclusters helps astronomers learn more about the large-scale structure of the universe.