In 3 dimensions, the only knot which bounds a disc is the unknot. But are there knots which bound a disc that is allowed to sit in the 4th dimension? The answer is yes, and we call these knots 'slice'. In my talk I will describe how to go about finding slice knots, what properties they have, why we are interested in them, and what open problems there are in the subject. I will not assume any prior knowledge of knot theory or topology.