This is a very simplified version of my homebrew fantasy world's map, minus any details I don't feel like sharing.

So, thousands of years in the past, after the world was done being made, there was just one huge continent. Some of the gods didn't like that so they split it into two separate ones, plus this big-ass island in the middle and a wee chunklet off in the corner. The Western Continent is mostly aspected with Ice, Water, and Wind energies, while the Eastern Continent is aspected with Fire, Lightning, and Earth. So the two climates are very different between them, and the various cultures are appropriately different.