The Mayans were right.
December 21, 2012. The day of the winter solstice. At 11:11 AM the Earth and the Moon line up with the Sun directly blocking the "center" of the Milky Way. When eclipsed from that center, The Earth was deprived of the cosmic energy that flows from the heart of the galaxy.
According to Humankind at the time, this is a certifiable end of the world.
The magnetic poles reversed instantly. North became south and south beame north in a moment. This dramatic reversal fried all electronics. Ley Lines crashed up out of the Earth, tearing space and time while pumping magic back into the world! The sky itself seemed to fracture, while the ground swelled, oceans surged, and the Earth broke and changed.
During this Fracture, as it was later named, dimensional portals opened, bringing in creatures from other realms. Whole forests and even mountain ranges were brought through, sometimes with disastrous results.
The Fracture also changed the power magic and technology has on the world. Now magic is the driving source of society. Ancient technology that has survived or has been recreated is met with fear and distrust.
The opening salvo of my world Terra Novo (not the first name, probably not the last). The ideas of it have been bouncing around in my head for over 4 years now. A bit has been typed out here and there (or copy and pasted from other sources), but mostly just bouncing around in my head. Going with the "only create what you need" theory of world building. In that 4 years I've been thinking about Terra Novo, I haven't even been playing D&D, so I haven't needed anything.
It's now 2812. Far enough from the Fracture that the first generation of elves born here has died. Human kingdoms have risen and fallen.
I used floodmap.net to make this, and a bunch of other maps. I think I'm going to use hexographer.com to make some "classic look" hex maps based off of these maps.