Earth

Earth is the third planet in the Sol System and is the home planet of the human race and various animals.

Introduction
Earth consists of seven geological continents, which offer a myriad of different meterological and geological climates, which are home to a significant diverse population of animals, all of which are believed to be carbon-based lifeforms. It was formed 4.6 billion years ago, and gave rise to single-celled organisms about 3.5 billion years ago. Later, a certain species of exceptional intelligence came to rise, Homo sapiens, otherwise known as the Human race, 200,000 years ago. The enigmatic race known as the Forerunners are believed to have came to Earth 100,000 years ago, constructing "machines" in Africa. Later, humans eventually began to show signs of sentience and made it into space in 1961. Several centuries after they became a spacefaring race, humans encountered a collective of intelligent, hostile extraterrestrials known as the Covenant, and later, the Flood.

Discovery of Earth
The Covenant originally had no knowledge about humanity's home world, mostly thanks to the development of the Cole Protocol. Sometime between the events of Halo: Combat Evolved and Halo 2, the Covenant eventually discovered Earth's location. The Prophet of Regret led a small expeditionary force consisting of 15 ships(2 assault carriers in the fleet), but was surprised to find that humans had inhabited the planet. At the end of Halo 2, the Covenant had eventually begun a full-scale invasion of Earth, and have completely overrun Africa by the beginning of Halo 3.

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

The Covenant had discovered a massive Forerunner structure several miles wide buried under the ground where the city of New Mombasa used to be. 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 galaxy, as the massive firepower that the Halos yield could destroy all life "with sufficient biomass to sustain the Flood within 3 radii of the galactic center," as stated by 343 Guilty Spark in the first Halo game.

Africa is the most important place on Earth in regards to the Halo story and the Covenant. Coincidentally, it is theorized to be the birthplace of humanity.

It is revealed through the storyline of the first two games that the Forerunners have some sort of connection to humanity.

Thus, the power of the Covenant was not fully dedicated into glassing Earth. Though the Covenant Fleet consisted of capital ships, flagships and such, several groups of the Covenant Fleet were stationed in the outer regions of the Milky Way Galaxy. In fact, much of the Covenant Fleet were still at Reach, while other parts of it were dedicated to finding more Halos and Forerunner technology and artifacts. Moreover, given that Cairo Station and its planet-side power generator are still intact at the end of Halo 2, it may be assumed that the UNSC is having some success in defending their homeworld, however small, with at least holding the Covenant forces at bay. The conclusion of the Second and the ultimate fate of Earth herself wait to be revealed in the campaign of Halo 3.

Planetside
Africa
 * Republic of Kenya
 * Mombasa
 * New Mombasa
 * New Mombasa Orbital Elevator
 * Old Mombasa
 * Voi
 * Diego Garcia - Island in the Indian Ocean
 * United Republic of Tanzania
 * Zanzibar Island

Oceania
 * Commonwealth of Australia
 * Sydney, Australia
 * HighCom Facility Bravo-6
 * Sydney Synthetic Intellect Institute

Asia
 * Korea
 * Kyonggi Province
 * Songnam
 * Special Warfare Center

North America
 * United States of America
 * Boston, Massachusetts
 * Chawla Base
 * Chicago, Illinois
 * Tactical Autonomous Robotic Defense System
 * Mexico
 * Base Segundo Terra - Mexico City, Mexico
 * Cuba
 * Havana
 * Centennial Orbital Elevator

Europe
 * Federal Republic of Germany
 * Essen
 * Beweglichrüstungsysteme Testing Facility

Orbital

 * Athens Station
 * Cairo Station
 * Malta Station
 * Nassau Station
 * Station Wayward Rest

Luna
 * Luna OCS Academy