This is the supercontinent Pangea, that existed 200 million years ago on Earth. It's remade in Minecraft as a huge (ca. 20000x20000 blocks) SMP map. The terrain is made in World Machine. It contains all 1.7/1.8 biomes, except for Mushroom Island, and they're populated in Vanilla Minecraft, instead of WorldPainter. WorldPainter is used on this map as a port for the terrain and to paint the biomes.