A look at the NCAA men's tournament, the 68-team free-for-all that begins Tuesday and ends three weeks from now at the Final Four in Atlanta:

1. WHO'S NUMBER 1?

Well, we won't know who the NCAA champion is until the Final Four is over on April 8. But the four No. 1 seeds heading into the tournament: Louisville, Kansas, Indiana and Gonzaga. The Cardinals are the overall top seed.

2. INTRODUCING THE DEFENDING CHAMPIONS ...

If you want to find last year's national champions, don't look in this bracket. After losing six players from its title team last year, Kentucky finished 21-11 and wasn't among the 68 teams in the tournament.

3. PICKING A WINNER ...

Louisville is where the smart money is going — the early 9-2 favorite in Vegas to win it all. But in order to guarantee picking the winner of all 67 games, you'd have to fill out more than 9 quintillion brackets. That's a 9, followed by 18 zeros. If you used one sheet of paper for each bracket, all that paper, according to one mathematician, would not fit inside the universe.

4. YAY FOR THE LITTLE GUY ...

But, please, don't call Gonzaga a little guy. Yes, it's the small Jesuit school in Spokane, Wash., undergrad enrollment 4,900. But this is a basketball powerhouse. The Bulldogs — better known as the Zags — have been in the tournament 15 years straight and made the Sweet 16 five times since 1999. They're led by 7-foot center Kelly Olynyk, who is widely regarded as one of the top players in the country. Oh, and remember the Butler Bulldogs, the team that made the national final in 2010 and 2011 with enrollment 4,500? They're seeded sixth in the East and their mascot, Blue II, is retiring after the season.

5. WHO-C-L-A?

Even with the loss of freshman star Jordan Adams, did any team in the bracket get a worse deal than UCLA? The Bruins, regular-season champions in the Pac-12, got a sixth seed in the South Region and have a tough matchup against Minnesota in their opening game. (Viewers responding to an unscientific ESPN poll Sunday night called that matchup as the most likely to produce an upset.) All part of a bad day for the conference, whose tournament champion, Oregon, was seeded 12th. Could've been worse, though. The Pac-12 put five teams in the tournament this year. Last year, this "Power Conference" only put one team, Colorado, in the hunt for a national title.

6. BIG EAST FAREWELL ...

Back in the 1980s, the Big East helped make basketball what it is today, with players like Patrick Ewing and Chris Mullin, coaches such as John Thompson and Lou Carnesecca, and its league tournament at Madison Square Garden. After this season, the conference as we know it will be history thanks to massive realignment that has overtaken college sports over the last few years. But the conference certainly isn't going quietly. Led by top overall seed, Louisville, the Big East placed eight teams in the tournament, more than any other league.

7. SENTIMENTAL JOURNEY ...

The St. Louis Billikens, No. 4 seed in the Midwest region, are wearing black ribbons on their jerseys with the word "Coach" emblazoned over them. They're honoring former coach, Rick Majerus, who died in December. The entertaining, portly coaching lifer made a career out of delivering basketball wisdom or a restaurant review with equal aplomb. His best run at March Madness came in 1998 when he led Utah to the title game.

8. GET YOUR TICKETS ...

There's a possible second-round matchup brewing in Salt Lake City between Arizona and New Mexico, two programs with some of the best-traveling, rowdiest fans in the country. It's a short flight from Tucson and Albuquerque to SLC. This will be among the toughest tickets to get in the first week.

9. BIG TEN POWER ...

The Big Ten was widely viewed as the best conference in basketball this season. Ohio State, Michigan State or both have made the Final Four in eight of the past 13 seasons. The Buckeyes, on a roll after winning the conference tournament Sunday, are seeded second in the West, while Tom Izzo's Spartans are third in the Midwest.

10. NAMES TO WATCH, THIS YEAR AND NEXT ...

You could see any of these players in the Final Four this year — or the NBA next year: Trey Burke (Michigan), Marcus Smart (Oklahoma State), Ben McLemore (Kansas), Cody Zeller (Indiana).