The Great Siege of Eridenne

A siege by the Bloodhorde of Pyrhem Wrathbringer lasting from 1240AC to 1241AC during the Pyrhem's Calamity .
This conflict ended up being a turning point of the Calamity, as the defenders of Eridenne held out long enough for Humanities Beckon to break the siege in 1241AC. Large swaths of the city were completely destroyed over the course of the siege, as sections were lost, and retaken countless time. The heart of the city and its great bastion remained intact, and from it, the heroes of Eridenne stood firm, and eventually reversed the tide. The key was the The Sentinels of Terrania and Valorie Boldwinter's Arcanium entourage discovering the Bloodhordes reliance on beacons of Malar. The strategic destruction of this beacons slowed the enemy's assault, giving the city the precious time, it needed to holdout against the overwhelming onslaught.