In tennis, the Grand Slam tournaments, the Masters Series tournaments and the Year-end Championship are considered the top-tier events of the men's professional tour annual calendar, in addition to the Olympics. They are collectively known as the 'Big Titles'. The ATP defined the mandatory events (Slams, Masters and YEC) as follows They are the biggest tournaments in our sport, where participation is mandatory, entry is reserved for the world’s best and success is rewarded with fame and a rich haul of points and prize money.