The Primeira Liga, often known outside of Portugal as the Portuguese Liga, is the top professional football division of the Portuguese football league system. The Liga NOS, as it is sometimes known, is contested by 18 clubs each season. Unlike many other European leagues, there is no relegation or promotion from the Primeira Liga to a lower division. The champion and runner-up of the season qualify for the following season's UEFA Champions League (group stage), while the teams placed 3rd to 5th enter the UEFA Europa League (group stage). The bottom three teams of the league get relegated to the LigaPro.The league format consists of playing each club twice, one home and one away. It is contested from August to May, with a third-place playoff and relegation playoff occurring at the end of each season. The Liga NOS is considered from one of the most competitive and challenging leagues in the world, with several high-level clubs competing for the championship title. The "Big Three" of Portuguese football are considered to be Sporting CP, SL Benfica, and FC Porto, all of which have won the Primeira Liga a combined 83 of the 87 championships contested since 1934. Popular players from the Primeira Liga include SL Benfica’s Raul Jimenez, who has scored more than 70 goals in 3 seasons, Sporting CP’s Bruno Fernandes, who has had one of the best careers in the league, FC Porto’s Otávio, who’s debut season garnered the attention of soccer fans worldwide, and Sporting CP’s João Mário, voted the best Portuguese player of the 2016/17 season.The Primeira Liga has seen record numbers in terms of attendance and viewership in recent years, with an average attendance of more than 20,000 per game and television viewership in the tens of millions. The league has also experienced success in European tournaments, with Sporting CP, SL Benfica, and FC Porto all making it to the Champions League Semi-Finals and SL Benfica making it to the Europa League Final in 2013.In terms of Portuguese Liga championships, Sporting CP is the leader with 36 titles, SL Benfica is in second with 33 titles, and FC Porto has the third most with 18 titles. The Primeira Liga is one of the top football leagues in the world and boasts some of the best players, owners, and coaches. With its strong international presence and dedicated fan base, Primeira Liga sure to remain one of the top leagues in Europe for years to come.