Europe was officially colonized in 2035. Thanks to the use of satellites, it was discovered that 0-12, a natural gas created on the planet, was extremely valuable: a single barrel could power a trip from Earth to Europa, and its potency allowed the journey to last only one month. The world's leading powers revived their space programs with the intention of capitalizing on this resource for themselves. Over the years, sabotage became constant, with ships being shot down in the atmosphere and even space assaults taking place over this precious resource. Meanwhile, on Europa, as more miners and supplies arrived from around the world, the outposts began to resemble cities from Earth. It was then, in 2060, that the atmosphere ignited: all nearby ships exploded and fell out of orbit along with the space stations. It is estimated that 200,000 people died in that single incident. Shortly after, it was discovered that it wasn't due to any accident with the cargo or anything similar. The young miners had rebelled against Earth. They had not been born in any specific country, but rather on Europa, and for most of them, there was no homeland to return to—except Europa itself.
In 2065, the first invasion of Europa was launched by the O.C.E.A.N.A. coalition, an alliance formed by all Earth-based planets. It was a total massacre: 80% of the transport ships were destroyed as soon as they entered the atmosphere due to Europa's new weapons, which were based on 0-12 and powerful enough to destroy a shuttle with a single shot. Ten percent of the fleet retreated, while the last 10% were forced to make emergency landings—essentially crashing into the planet—to avoid being destroyed from orbit. In total, 100,000 people landed on Europa. One day later, all contact with them was lost. It is estimated that 3 million soldiers died in the atmosphere in a single day. It was considered the bloodiest day in human history, remembered as March 7th.
Realizing that a full-scale invasion was nearly impossible under those conditions, O.C.E.A.N.A. ordered the bombardment of Europa—a constant rain of artillery from the skies that lasted 365 days over former colonies and military zones. The number of casualties is unknown.
In 2067, O.C.E.A.N.A. launched a new invasion in the northern hemisphere of the planet, where they managed to establish a base of operations for ground troops. There are no reports of what they encountered upon arrival.
By 2070, Europa was practically unrecognizable from its first colonization. The planet was filled with trenches, and most of the local population had taken refuge at the South Pole in a last-ditch effort to build a stronghold for resistance. What remained of their army carried out skirmishes from the old mines that covered the planet, drastically reducing all attempts to extract the gas.