Earth



Earth is the third planet in the Sol planetary system and most notably inhabited by human beings, its dominant and only intellegent species. Shortly after the humans' first development of teleportation technology, a spontaneous portal gateway was established with the distant planet of Xen in 2000. This caused a major resonance cascade (at the location of the portal, during an "incident" at the Black Mesa Research Facility) that led to Earth's infestation of creatures from Xen. The portal ultimately allowed members of the Combine Empire to invade and conquer the entire planet after a violent seven-hour conflict against the human race. The Combine eventually enslaved the human race and exploited Earth's natural resources, such as when the oceans were completely drained

A relatively small ban of humans, known as the Resistance, united to overcome the Combine's rule on Earth. The outcome of their efforts is unknown.