Eye liner is a cosmetic used to define the eyes. It is applied around the contours of the eye to create a variety of aesthetic illusions such as depth and lenght or to emphasize the eye color. Eyeliner was first used in Ancient Egypt and Mesopotamia .
In the late 20th and early 21st century, heavy eyeliner has been associated with Gothic fashion. Here's a picture I found on the internet about how you could put eyeliner on your eyes and create amazing works of art :)