Africa is a continent on Earth, and is the second-largest continent after Asia. At about 30,221,532 km² (11,668,545 mi²) including adjacent islands, it covers around 6.0% of the Earth's total surface area, and 20.4% of the total land area. The continent is bordered by the Mediterranean Sea to the north, the Suez Canal and the Red Sea to the northeast, the Indian Ocean to the southeast, and the Atlantic Ocean to the west. Africa, particularly central eastern Africa, is widely regarded within the scientific community to be the origin of humans and the Hominidae family (great apes), as evidenced by the discovery of the earliest hominids and their possible ancestors, as well as later ones that have been dated to around seven million years ago – including Sahelanthropus tchadensis, Australopithecus africanus, Australopithecus afarensis, Homo erectus, Homo habilis and Homo ergaster – with among the latest being Homo sapiens found in Ethiopia being dated to ca. 200,000 years ago. 
Africa has always played a key role in human history, being the likely birthplace of humanity as a species. Periodical waves of outward migration resulted in the spread of several species to more distant parts of the world, including the earliest known migrations of Homo erectus, and several later migrations of Homo sapiens. By the time humanity first settled other worlds beyond Earth, however, it was not even known with certainly that Earth was humanity's planet of origin, let alone Africa the respective continent from whence it emerged. Following the conclusion of the human-Forerunner wars, the humans that were permitted to live on were taken to Earth and were given over to the care of Lifeworkers for observation and study. The Librarian herself gave many humans geas at that time. As the last years of the Forerunner-Flood war waned, the Conservation Measure saw species from all across the globe collected for future preservation, in one way or another. It was from Africa that the Librarian oversaw her efforts on Earth, and it was there she remained even up unto the point where star roads and the Flood entered the Sol system. Her last act was to set the construction of the Portal in East Africa into motion. It would go on to be completed after the firing of the Halo Array, but even after humans were returned once more to the planet, it lay dormant, eventually being covered by the Earth as the years went on.
Rise of humanity
Battle of Earth
On October 2552, the Prophet of Regret found Earth in search of the Portal. They landed only in one spot in the country of Kenya, in and around the city of Mombasa. Regret's forces tried to hold onto and capture the city from the UNSC Defense Force, but failed. Then, his flagship, Solemn Penance, jumped into Slipspace, damaging the city. After this, more Covenant ships appeared, glassing Mombasa and its surroundings to uncover the Portal to the Ark, which had been buried under the ground for more than a hundred thousand years.
Four weeks later, the uncovering process of the Portal was complete. The Prophet of Truth came to Earth on his Forerunner Dreadnought, landing in the center of the Portal. The UNSC, believing the structure to be the Ark, attempted to stop the Covenant from activating it, with no effect. Truth and his fleet escaped through the Portal, and a Flood-infected ship arrived just after, followed shortly by the Sangheili. To prevent the Flood from spreading and consuming the planet, the Fleet of Retribution glassed a large portion of the continent, bringing a bitter and violent close to the battle.
In 2555, the portal was activated again, leading to a massive invasion of Earth by Retriever Sentinels sent by 000 Tragic Solitude, that was stopped by the human and Sangheili forces at Installation 00.
List of appearances