Carbon Nanotubes, that is:

Pound for pound, carbon nanotubes are stronger and lighter than steel, but unlike other materials, the miniscule cylinders of carbon – which are no wider than a strand of DNA – remain remarkably robust even when chunks of their bodies are blasted away with heat or radiation. A new study by Rice University scientists offers the first explanation: tiny blemishes crawl over the skin of the damaged tubes, sewing up larger holes as they go.

You would think that one would have to design a structure specifically to have this kind of capability, but no. These things are just naturally self-healing. That's pretty cool, seeing as much of our world may soon be made out of them.

Via GeekPress.