From Halopedia, the Halo wiki
Emerald Cove was a human colony world of the Unified Earth Government. The colony was known throughout human space as a world of sublime beauty, with thousands of miles of white sandy beaches, azure oceans, and "beautiful colonists that made any trip there a happy one". With an archipelagic environment, Emerald Cove was both a destination for tourists and the United Nations Space Command.
During their training, the Spartan-IIs were sent on an underwater mission to Emerald Cove with Chief Petty Officer Franklin Mendez. Mendez sabotaged half of the Spartans' air tanks to test them; they stole his in retaliation. Afterwards, the Spartans abandoned their training and hid out on a deserted island for a week, lighting bonfires, baking clams, and surfing. After Madrigal was glassed in 2528 by the Covenant, Kojo Agu took residence on Emerald Cove in the city of Holetown. The colony was also the homeworld of Michael Sullivan, Senior Communications Director of the Office of Naval Intelligence.
In 2542, during the Human-Covenant War, the UNSC abandoned Emerald Cove due to the threat of nearby Covenant forces. However, Emerald Cove's fate remained unknown as of 2552, with some questioning if the world was glassed or occupied by the Covenant, or simply left untouched by the alien empire.
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