Tattoos contain permanent color particles with metal salts, plastic and chemicals rather than natural vegetable colors. Tattooing developed in many cultures as a way to mark the skin through various techniques like pricking, puncturing or tapping pigment into the skin. Evidence of some of the earliest tattoos date back to around 3300 BC on the Iceman mummy, though Egyptian and Nubian mummies from around 2000 BC also contained tattoos.