Just how do you use your pee to start a fire? We've always thought of the opposite. Using pee to put a fire out. But if you're camping, and you're a survivalist, this is one of the things you'll need to know.
The technique involves wrapping your pee up in some plastic wrap and this will act as a lens for the sun's rays. You can also use plain water too actually, but if there's no water around you, pee will have to suffice. Watch the video after the break on how they MacGyvered it.