Aurora Cascade

In the year 4,326, a prominent empire in the southern reaches of the Southern Continent suffered a catastrophic backlash from solar activity impacting their mana receptors. Wild energies spilled out into the landscape, mutating flora and fauna as numerous towns and cities were devastated. The so-called Aurora Cascade has been used as a cautionary tale ever since, lest any empire try to duplicate the mana receptor network.
The empire, known formally as the Triple Alliance for the three kingdoms who came together, may have been the most magically and technologically sophisticated human empire in Kytheria, before or since. They were unusual for being so distant from the equator; it's well known that not only the Girdle's energies, but prana- the 'breath of the world' that allows many magitech items to work- is strongest near the center of the world. The Triple Alliance had brilliant wizards and a long tradition of magical study, and when its wizards created the first mana receptor, the empress at the time immediately saw its potential. The receptors themselves were easy to fashion and served to draw energies from the Girdle and make them more accessible to wizards, resulting in more potent magics than even the mightiest wizards near the equator. These energies were funneled into civic projects and warmachines, skyships and research, flooding their civilization with the Girdle's bounty. Sages who studied the sun warned that there could be complications, for it was noted that every eleven years or so the aurora picked up in intensity, and the first receptors at this time were prone to overloading and requiring calibration. The empress and her staff ignored these warnings, since the receptors had been modified and improved since their inception, and her grand dream of a receptor network capable of drawing energies even during the summer solstice (when the empire faced the Girdle the least) finally came true. Two hundred receptors laid out in geomantic patterns now powered the kingdom and its wizards. 
As the sun headed toward its next maximum, some sages noted with concern that the receptor network was behaving somewhat erratically, but again they were ignored. During the summer solstice however, the sun reached a critical point and the receptors- now too numerous and well connected for safety measures to be effective- overloaded spectacularly. Magical energies twisted the land itself and caused some towns to explode, others to warp horribly, and some to disappear entirely. The Imperial Palace became encased in an opaque crystalline dome that stands to this day, and sadly much of the knowledge in the various wizarding schools of the Triple Alliance were lost in the catastrophe.