|Find out what it's like to play on clay|
|Around the Academy:
The distinctive red suface of clay is made of crushed brick packed together and covered with a loose, rough layer.
This causes the ball to stick to the court, slowing it right down.
It also gives the ball a big bounce - with players often having to play the ball at shoulder height or above.
This gives players more time to reach the ball and makes it harder to put shots away.
It's difficult to win points with one big shot.
That's why patience is a virtue on clay courts.
Indeed, research shows that rallies measured at the French Open are longer than at any other Grand Slam event.
It is not unusual for a rally to last 10 to 15 strokes, compared with two or three on grass.
Because the ball has such a big bounce on clay, it is important to play the ball deep and to put plenty of spin on it.
The slippery surface can force players to skid into shots and points can often be won by wrong-footing your opponent.
Like grass, clay must be watered.