The NBA is a professional basketball league in the United States. The league has 30 teams that compete in two conferences, the Eastern Conference and the Western Conference. The best teams play in the playoffs to determine a world champion. The NBA was founded in 1946 and is headquartered in New York City. The NBA has an international presence with teams in Canada and Australia. The league also has franchises in Europe and Latin America. The NBA is one of the most popular sports in the United States, and it has many famous players.

The game of basketball was invented in Springfield, Massachusetts in 1891. James Naismith, a graduate student at MIT, was inspired by the Indian game of lacrosse and wanted to create a sport that would combine endurance, hand-eye coordination, and jumping ability.

In the early years of the NBA, the league struggled with money-losing franchises, low attendance, and declining television ratings. The NBA reformed under commissioner David Stern in 1984 and began to grow into an international entertainment company. The league introduced aggressive marketing that highlighted superstar players such as Magic Johnson and Larry Bird, transforming the NBA into a global brand. The league also increased its emphasis on player safety and health.

As the NBA expanded, it became more lucrative for team owners. By the 1990s, the NBA had ascended to the pinnacle of American pop culture and had become the most profitable sports league in the world. The NBA has a rich history of legendary teams, such as the Boston Celtics of Bill Russell and Elgin Baylor, and great individual players, such as Michael Jordan, Kareem Abdul-Jabbar, and Magic Johnson.

Each year, the top eight teams in each conference compete in a series of best-of-seven games to determine the division champion and the overall NBA champion. The playoffs are held in late April and May. The first four teams in each division and the top two wildcard teams advance to the semifinals, then the finals. The winning team is declared the NBA champion, and the runner-up is named the Eastern Conference champion.

The current roster of NBA players consists of a maximum of 15 active players per team. Each game consists of four quarters and two overtime periods, and the clock is set at 24 seconds. A player has 10 seconds to score a basket, and the clock resets after each turnover or foul.

There are a total of 82 regular-season games, which means that each team plays 56 games each season. Teams in the same division will play each other twice a year, and they will play teams from other divisions once each season. The schedule starts with an opening night matchup between the Milwaukee Bucks and the New York Knicks on Nov. 3. The rest of the opening week includes games between the Chicago Bulls visiting the Cleveland Cavaliers and the Washington Wizards visiting the Indiana Pacers. The other games in the group will be between the Atlanta Hawks and the Detroit Pistons, and the Miami Heat and Carlotte Hornets.