Lava flow… inside a cave. That’s right. You spawn inside a mountain completely underground (no natural exit) right beside a lava flow that lights up the cave.
The best seed in the world? It’s a long known, and much loved seed. If you don’t know it, get ready for a cool spawn. Does the name live up?
UPDATE: Thanks to the comment by Supercrafter below, because we all now know… There’s coal, redstone, and most importantly, diamonds if you dig one block to the left, then straight down, from the spawn site. See Supercrafter’s comment below!