Light is not the only fastest thing in the world that holds this label. There are a lot of things in the world that go fast in other categories. From man-made machines to Eminem, who holds the record as the fastest rapper — even the speed of light has nothing against them. Some of these have even earned a place in the Guinness Book of World Records! As with anything in this world, there are certain rules that the fastest things in the world must follow to earn that sweet “quick” label.