2003: The Resonance Cascade

Humanity unexpectedly found itself fighting for its life on a seemingly arbitrary Friday in 2003 when, early in the morning, EAS broadcasts took over regular television scheduling, first in New Mexico, then the United States, and finally the whole world.

By Saturday morning, militaries worldwide will have finished deploying their armed forces to fight against the Xenian threat that has ravaged throughout the planet. It has become too late to try to contain the outbreak, let alone the knowledge of the Xenian creatures.

Then, just as fast as it started, it ended. By Friday next week, Humanity has established safe zones in major cities, and as luck would have it, the portal storms finally started becoming less frequent, giving the armed forces a fighting chance. Casualties were high, especially among civilians, but in the safe zones, it became apparent that humans could one day get rid of the Xenians once and for all as long as the portal storms stopped.

2004: The 7-Hour War

Almost a year after the event, the 7-hour war happened. Except, it wasn't 7 hours at all.
Humanity never did surrender, fighting with everything they had; however, what seemed to seal the deal was not just the fact that humans hadn't yet lost but the fact that the unknown assailants had, rather abruptly, decided to retreat with their forces. Immediately after that, most of all, Vortigaunts were gone entirely off the face of the planet, with few remaining in hiding.

No one truly knows what happened to the Vortigaunts. However, speculation is that they were captured and forcefully removed from the planet by the unknown assailants, the purpose of this remaining unknown.

2021: A New Age for Black Mesa

In 2021, humans have already managed to reclaim Earth for themselves. With portal storms not having happened for over six years now, the safe zones have been closed down, and the old cities are being rebuilt for the most part.

There have been many structural changes in how governments work around the world. Humanity has become much more united, but it is healing. The economy has taken a significant hit, too, leaving some people with far too much money and others with far too little.

At this very year, numerous civilian benefactors decided it worthwhile to recreate the infamous research facility, using the exact locations and name; however, other staff and very different goals.

The inception of the research facility has been highly controversial, given that Humanity mostly blames Black Mesa for its part in the Resonance Cascade and the consequent Xenian attacks and worldwide war.

Sector C will be the first one to open; construction is expected to complete around 2025.