The Royal Rumble is a professional wrestling event produced annually in late January since 1988 by WWE the world's largest professional wrestling promotion. It is named after the Royal Rumble match a modified battle royal in which the participants enter at timed intervals instead of all beginning in the ring at the same time. After the inaugural 1988 event aired as a television special on the USA Network the Royal Rumble has been broadcast via pay-per-view since the 1989 event and livestreaming since the 2015 event. It is one of WWE's five biggest events of the year along with WrestleMania SummerSlam Survivor Series and Money in the Bank referred to as the "Big Five".