Earth

Earth is the home planet of humans, it consists of seven continents. It is home to a wide array of different creatures. Earth's history goes back as far as millions of years B.C. when the first single celled organisms started to evolve into more and more advanced creatures. When the creatures became sentient, they began building advanced civilations that far surpassed what other animals could create.

Many theories about Earth erupted when the Halo 3 Announcement Trailer was shown.

The Covenant, buried in the Earth's crust, had discovered a massive Forerunner structure probably the size of High Charity (as it dwarfs the mighty 5 kilometer long Covenant Assualt Carriers that make up the "excavation force.") Is this the Ark? If so, why was it on Earth?

The Prophet of Regret had obviously come to Earth in search of a Forerunner artifact that might determine the fate of all sentient life in the face of the galaxy, as the massive firepower that the Halos yield could destroy all sentient life "within 3 radii of the galactic center," as stated by a Monitor in the games.

Africa is the most important place on Earth, it seems, and, coincidentially, it is theorized to be the birthplace of humanity.