To a first-time observer Curling might look like a sport where people are simply throwing rocks down an ice track. But there is much more to curling than meets the eye. It is the only sport in the world where players have the ability to affect the outcome of their actions after the fact. In other words the trajectory of a curling stone can be influenced even after it’s released. Achieving the perfect balance of skill, athleticism and physics in curling is one of the Olympics’ greatest challenges.