Grass courts have been a staple of tennis since the late 1800's. Surprisingly, the courts are made with mixture of different types of grasses, not just one, depending on the tournament. And they've become rarer to find.
Grass courts are still the most traditional court type, but they require more maintenance than other courts which is why there aren't many grass court tournaments on tour. The court type is most common in Europe, specifically in Great Britain, but there are some grass courts in Germany, Spain and even the United States.
With Wimbledon currently underway, see how much you know about the history of grass.