What happened to the Well of Eternity
Sargeras gathered his vast Burning Legion and made his way towards the unsuspecting world of Azeroth. The Legion was comprised of a million screaming demons, all ripped from the far corners of the universe, and the demons hungered for conquest. Sargeras' lieutenants, Archimonde the Defiler and Mannoroth the Destructor, prepared their infernal minions to strike.
Queen Azshara, overwhelmed by the terrible ecstasy of her magic, fell victim to Sargeras' undeniable power and agreed to grant him entrance to her world. Even her Highborne servitors gave themselves over to magic's inevitable corruption and began to worship Sargeras as their god. To show their allegiance to the Legion, the Highborne aided their queen in opening a vast, swirling portal within the depths of the Well of Eternity.
As a titanic battle raged between Queen Azshara's and Malfurion Stormrages' forces around Azshara's capital city, the delusional queen waited in anticipation for Sargeras' arrival. The lord of the Legion was preparing to pass through the Well of Eternity and enter the ravaged world. As his impossibly huge shadow drew ever closer to the Well's raging surface, Azshara gathered the most powerful of her Highborne followers. Only by linking their magics together in one focused spell would they be able to create a gateway large enough for Sargeras to enter.
Malfurion, convinced that the Well of Eternity was the demons' umbilical link to the physical world, insisted that it should be destroyed. His companions, knowing that the Well was the source of their immortality and powers, were horrified by the rash notion. Yet Tyrande saw the wisdom of Malfurion's theory, so she convinced Cenarius and their comrades to storm Azshara's temple and find a way to shut the Well down for good.
The ensuing battle between Malfurion and Azshara threw the Highborne's carefully crafted spellwork into chaos. The unstable vortex within the Well's depths exploded and ignited a catastrophic chain of events that would sunder the world forever. The massive explosion rocked the temple to its foundations and sent massive quakes ripping through the tortured earth. As the horrific battle between the Legion and the night elves' allies raged around and above the ruined capital city, the surging Well of Eternity buckled in upon itself and collapsed.
The resultant catastrophic explosion shattered the earth and blotted out the skies.
As the aftershocks from the Well's implosion rattled the bones of the world, the seas rushed in to fill the gaping wound left in the earth. Nearly eighty percent of Kalimdor's landmass had been blasted apart, leaving only a handful of separate continents surrounding the new, raging sea. At the center of the new sea, where the Well of Eternity once stood, was a tumultuous storm of tidal fury and chaotic energies. This terrible scar, known as the Maelstrom, would never cease its furious spinning. It would remain a constant reminder of the terrible catastrophe... and the utopian era that had been lost forever.