Geological / environmental event
An incredible earthquake affecting southwest Kasetia and the Arrow Isle, leading to the destruction of much of the city of Enaveirveiro, with much of it sinking into the ocean.
In the early morning of Flamerule 21, the tectonic plates of Kasetia collided at the fault below the city-state of Enaveirveiro. This brought an earthquake with such force and intensity that parts of the city broke off into the water, with buildings collapsing down into the depths of the bay nearby.
This created the Torsional Straits as they are now known and led to a huge shift in town planning for Enaveirveiro. It also led to the founding of Espetania.