NCAA Men's Basketball Championship

The NCAA Men's Basketball Championship is a single-elimination college basketball tournament held each year to determine the season's national champion. The tournament has been held every year since 1939, though its format has changed significantly since those first early tournaments.

Now, the tournament invites 68 college basketball teams to compete in four regions. The winners of each region unite in the Final Four, one of the nation's most-watched sporting events. Those 68 original berths are filled both by the tournament champions from each of the NCAA's conferences and then by at-large teams, which are invited by the NCAA selection committee.

The NCAA tournament takes place each March and has become known familiarly as "March Madness" or the "Big Dance." UCLA holds the record for the most NCAA titles with 11.

Kentucky is the defending champion, after beating Kansas in the 2012 national championship game. The win gave Kentucky eight national championships, second-most among Division I schools.

The initial NCAA men's basketball tournament, played in March 1939, featured a field of just eight teams -- all winners of district playoffs throughout the country -- in a single-elimination competition with games played in Philadelphia, San Francisco and Evanston, Ill.

In 1951, the tournament field doubled in size (while maintaining its single-elimination format), with 10 of the 16 spots given to conference champions who automatically qualified. The field grew even further two years later, when 22 teams took part (and an additional round with some byes was added).

The NCAA tournament consisted of 22 to 25 teams through the early 1970s, before a major change came in 1975. That year, the NCAA began inviting "at-large" teams (schools that were not their conference champions) and increased the field to 32 teams.

Teams were seeded for the first time in 1978, one year before another expansion brought the number of participating teams to 40. In the early 1980s the field grew to 52 teams in 1983 and 53 teams in 1984, with a number of opening-round games added and the top two seeds in each region given first-round byes.

Those byes disappeared in 1985, when 64 teams were first selected to compete in the NCAA tournament. Teams were seeded 1 through 16 in each of four regions, with six rounds of games (over three weekends of play) required for teams to reach the championship game.

In 2001, as additional conferences became recognized by the NCAA, the field was expanded to include 65 teams. That year, a play-in game between the two lowest-seeded teams from one region was added (played two days after Selection Sunday) to determine which team would play the top seed in that region.

The NCAA implemented a "pod" system for the first two rounds at the 2002 tournament, allowing the top four teams from each region to play at a site as close to home as possible, without regard to that school's tournament region. (All teams playing at a first- or second-round site fed into the same regional tournament.)

The 2011 NCAA men's basketball tournament consists of a 68-team field. The first round is comprised of just four games, two of which feature matchups of the two lowest seeds in a region, with the winner playing that region's top seed in the second round. The other two matchups in the first round pit the lowest seeded at-large teams from a region, with the winner slotting in to play the fourth- or fifth-seeded team in that region (depending on how low those first-round participants are seeded).

The first NCAA tournament was held in 1939 and organized by the National Association of Basketball Coaches. Eight teams participated in the tournament, held in Evanston, Ill. Oregon, coached by Howard Hobson, won that first title, defeating Ohio State in the finals. Attendance was 15,025.

At that time, the NCAA tournament actually was considered less prestigious than the National Invitation Tournament, a college basketball tournament held in New York since 1938. Teams were able to choose to go to either the NIT or the NCAA tournament -- or both -- and, in the early years, squads often chose the NIT.

In 1940, the NABC handed authority of the NCAA tournament over to the NCAA itself. In 1944, Utah won the NCAA tournament that year, having also participated in the NIT. The City College of New York also participated in both 10 years later and, after winning the 1950 NCAA tournament and NIT, became the first (and only) program to win both championships in a single year.

At that time, Adolph Rupp's Kentucky team was the squad to beat -- the Wildcats won a first title in 1948 and then repeated in 1949, 1951 and 1958, all under Rupp's leadership. By the mid-1950s, the NCAA had increased the tournament's field to 25 teams, and it had grown in prestige to become considered more impressive than the NIT.

Shortly after, the domination of John Wooden and his UCLA squad began. Wooden won his first title with the Bruins in 1964, and he went on to win nine of the next 11 tournaments, including seven straight between 1967 and 1973. Wooden's final title came in 1975, his final year as head coach of the Bruins.

In 1971, the NCAA banned schools participating in its tournament from playing in any other competitions (such as the NIT). By then, the NCAA generally had the stronger selection of the college field, and the NIT chose from the schools not invited to the NCAA.

The NCAA decided to expand its field again a few years later, when it decided to invite "at-large" teams for the first time. That change is believed to have been motivated strongly by the ACC's field in 1974. That year, Maryland and NC State were two of the best squads in the country. The two teams met in their conference tournament in a 103-100 overtime grudge match, still considered one of the best games in college basketball history.

NC State won that game and went on to win the NCAA tournament. Maryland, having lost its conference title, was not even invited to the Big Dance. But starting the next year the NCAA invited at-large squads such as Maryland to participate, increasing the field to 35.

The term "March Madness" had been coined decades earlier, but it was in the 1980s that fans began associating the words with the NCAA tournament. The NCAA earned a dual-use trademark for the term in the 1990s, guaranteeing that March Madness was used solely according to its control. Now, the term refers more generally to the basketball championships in March, including the NCAA tournament, conference tournaments and women's tournaments.

CBS has aired the NCAA tournament since 1982, usually sharing coverage with ESPN or with its partners, such as TBS or TNT. Beginning in 2003, CBS expanded its coverage to include live streaming on the Internet, usually through its partners Yahoo! or AOL, to make out-of-network games available to viewers.

In 1985, Villanova became the lowest seed ever to reach the national championship game, doing so as an 8-seed. Villanova defeated a No. 1 seed, Georgetown, in the finals, a game still considered one of the biggest upsets in college basketball history. Since then, no lower-seeded team has reached the championship game. The next year, though, 11-seed LSU became the lowest seed to reach a Final Four. George Mason also reached the Final Four as an 11-seed in 2006.

Only once has the Final Four been made up of all No. 1 seeds, in 2008. No. 1 seeded Kansas, Memphis, North Carolina and UCLA all won their regions and reached the Final Four. Kansas and Memphis' championship matchup was one of only six finals that were played by two No. 1 seeds. Conversely, there have been only three years in which no No. 1 seed made the Final Four -- in 1980, 2006 and 2011.