Halo Installations are massive, ring-shaped structures created by the ancient race known as the Forerunners. These installations serve multiple purposes, including habitat, research, and as a means to contain the parasitic threat known as the Flood. Each installation is equipped with advanced technology and ecosystems, supporting various forms of life. There are seven known Halo Installations, each designated by a number. The most famous is Installation 04, which plays a central role in the Halo video game series. The primary function of these rings is to eliminate all sentient life in the galaxy to stop the spread of the Flood, making them both powerful and dangerous.