Bowling refers to a series of sports or leisure activities in which a player rolls or throws a bowling ball towards a target. In pin bowling variations, the target is usually to knock over pins at the end of a lane. In target variations, the aim is usually to get the ball as close to a mark as possible. The pin version of bowling is often played on a flat wooden or other synthetic surface (can be oiled in different patterns for different techniques), whilst in target bowling, the surface may be grass, gravel or a synthetic surface. The most common types of pin bowling include ten-pin, nine-pin, candlepin, duckpin and five-pin bowling, while in target bowling, bowls, bocce, carpet bowls, pétanque and boules, both indoor and outdoor varieties, are popular. Today, the sport of bowling is enjoyed by 100 million people in more than 90 countries worldwide.