All blocks, mobs, including players, are invisible.

The worst thing that could possibly go wrong for me, went wrong. My minecraft world, which I have put over a hundred hours into, placed, broken, and crafted a total of over 200,000 blocks, DISAPPEARED!.

What I expected to happen is to be able to see anything other than entities, beacons, and every possible viewpoint in loaded the loaded chunks.

What actually happened was I saw nothing but the wire frame of blocks, beacon beams, entities such as pork chops and exp orbs on the ground. I couldn't even see myself in third person (F5 mode), or in my inventory.

I do not know how to reproduce this game-breaking bug.