Serie A is the top-tier football Italian men's professional league, founded in 1898. It is considered one of the best football leagues in the world. It is contested by 20 teams and operates on a system of promotion and relegation with the Serie B. The annual system of the league is divided into two seasons; Spring (February to May) and Autumn (August to May) during which each team plays 38 matches, playing one game against each team twice. Serie A is the most watched direct broadcast football league outside of the United Kingdom and has featured some of the biggest and most popular teams, players, and international super stars. It is the oldest national football league in the world, the active clubs in Serie A have over 20 million fans.The most successful team of all-time is Juventus, who have won 36 Serie A titles. The Turin-based club have won the last nine titles and are the defending champions. Other popular teams in the top tier include AC Milan, Internazionale (Inter Milan), Fiorentina, Roma and Napoli. The Rio-based AS Roma have three titles whilst Inter Milan, Fiorentina and Napoli have won the Italian title twice. Other popular teams such as Genoa, Lazio, Sampdoria, Parma and Bologna have never won a Serie A title.The top four teams at the end of the regular season qualify for the UEFA Champions League, whilst the teams that finish 5th-7th qualify for the Europa League. The last two have to participate in the UEFA Europa Conference League. At the end, the three teams which collect the fewest points and consequently find themselves in the last three places of the table are relegated to Serie B.The Serie A top scorer of all time is Silvio Piola with 274 goals. The highest goal scorer of the season in 2020/21 was Italian striker Cristiano Ronaldo, who scored 29 goals in 34 matches for his team Juventus. Ronaldo holds the all-time record for most goals scored during a Serie A season, having previously notched 31 in the 2019/20 season. The most capped players in the history of the league are Alessandro Del Piero with 705 appearances and Paolo Maldini with 647 appearances. The league is one of the top European leagues in terms of attendance and boasts some of the most passionate fans in the world. The average attendance per match throughout the 2020/21 season was just over 22,000.Serie A has produced some of the greatest players of all time, such as Gigi Buffon, Fabio Cannavaro and Alessandro Del Piero, as well as world-renowned stars such as Zlatan Ibrahimovic, Ronaldinho and Cristiano Ronaldo. It is also known for its passionate and vibrant atmosphere during matches, which makes Serie A one of the most popular leagues in the world.