Gao

Gao is a remote human colony, administrated by the Unified Earth Government, that survived the Human-Covenant War. Beneath the planet's surface, there is a vast cavern system renowned for its therapeutic effects and alleged inexplicable cures. Gao is also home to several Forerunner artifacts.

In 2553, a UNSC research battalion protected by Blue Team arrived at the planet. At the same time, citizens of Gao were discovered in the cave system, having been brutally murdered. Special Inspector Veta Lopis of the Gao Ministry of Protection was assigned with investigating the serial killer. Her search led her to the possibility that the killer may be hiding within the Spartan ranks, as the situation turned into a crisis. When the UNSC discovered the planet's Forerunner artifacts, politicians of Gao's planetary government, loyal to Insurrectionist groups, aligned with a dangerous Covenant remnant faction to prevent the UNSC from utilizing the Forerunner technology.

Trivia
The planet may be named after a city of the same name in Mali.

List of appearances

 * Halo: Last Light