Camouflage is the way in which some animals are coloured and shaped so that they cannot easily be seen in their natural surroundings.
It's important for certain animals to be able to blend in with the environment so that predators can't see them.
Artist Liu Bolin from Beijing, China is exploring the idea of camouflage in his artwork.
He paints himself so that he matches the background perfectly.
Then he photographs himself in the scene.
These are amazing.
It took me a minute or two to even find Liu in the bulldozer picture below.