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.

Earth holds significant oceans and bodies of fresh and salt water, and also a mostly nitrogen atmosphere, although it contains oxygen to facilitate aerobic respiration.

History
The Earth 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 - First landing site of Covenant forces on Earth, destroyed in ensuing attack and retreat during the First Battle of Earth.
 * New Mombasa
 * New Mombasa Orbital Elevator
 * Old Mombasa
 * Voi - A town further inland from Mombassa and a source of major battles during the Second Battle of Earth
 * Diego Garcia - Island in the Indian Ocean and a major UNSC base.
 * United Republic of Tanzania
 * Zanzibar Island - Location of Wind Power Station 7

Oceania
 * Commonwealth of Australia
 * Sydney, Australia
 * HighCom Facility Bravo-6 - Home of HIGHCOM and HQ of the UNSC.
 * Sydney Synthetic Intellect Institute - A.I. research institute.

Asia
 * Korea
 * Kyonggi Province
 * Songnam
 * Special Warfare Center - Testing and training area, famous for testing the MJOLNIR MK VI and the C and V variants

North America
 * United States of America
 * Boston, Massachusetts
 * Chawla Base - An ONI base that housed the artifact from I Love Bees
 * Chicago, Illinois
 * Tactical Autonomous Robotic Defense System
 * Mexico
 * Base Segundo Terra - Mexico City, Mexico. Used as the staging area on the attacks on the Yucatan Peninsula and Havana.
 * Cuba
 * Havana
 * Centennial Orbital Elevator - A 200 year old antiquated Space Elevator that was destroyed during the Second Battle of Earth.

Europe
 * Federal Republic of Germany
 * Essen
 * Beweglichrüstungsysteme Testing Facility - Testing site of the C Variant MJOLNIR MK. VI

Antartica
 * Mount Erebus - Site of a Covenant attack during the Second Battle of Earth.

Orbital

 * Athens Station - A ODP defending Earth, destroyed by borders in the First Battle of Earth.
 * Cairo Station - A ODP defending Earth. It was the command center of Earth's Defence by Admiral Hood.
 * Malta Station - A ODP defending Earth, destroyed by borders in the First Battle of Earth.
 * Nassau Station - A ODP trapped in the 21st century by a slipspace "bubble".
 * Station Wayward Rest - Termination point of the COE. Destroyed during the Second Battle of Earth.

Luna
 * Luna OCS Academy - Training center of Naval personel.