The modern game of tennis as we know it started to develop in the late 19th century in England. The first Wimbledon Championship was held in 1877. Tennis spread throughout the world in the early 20th century and became an Olympic sport in 1896. The four major tournaments, also known as Grand Slams, were established: Wimbledon, the US Open, the French Open, and the Australian Open. Today, tennis is played by millions of people, both recreationally and professionally.