A tattoo is a form of body modification in which ink or pigments are inserted into the skin to create a design or image. Tattoos can be created by puncturing the skin with a needle and injecting ink into the dermis layer of the skin. This causes the ink to become permanent, as the body cannot naturally remove the pigment. Tattoos can vary in size, design, and color, and are often used as a form of self-expression or to commemorate an event or person. The art of tattooing has a long history and has been practiced in many cultures throughout the world.