The championship game of the U.S. National Football League -- the Super Bowl
-- is the biggest sporting event in the United States. And it's a spectacle that has a growing international audience.
More than 100 million people in the U.S. and around the world are expected to tune on Sunday when the NFL's Baltimore Ravens and San Francisco 49ers meet in Super Bowl XLVII at the Superdome in New Orleans, Louisiana.
Baltimore Ravens quarterback Joe Flacco looks towards the media during football practice, Jan. 26, 2013 in Owings Mills, Md.
The game features two physical, bruising teams with stingy defenses and top-notch quarterbacks. Ravens quarterback Joe Flacco, who has been to the playoffs in each of his five NFL seasons, has taken his game to another level. He has posted stellar statistics in Baltimore's three playoff wins this year, including eight touchdown passes and no interceptions. He also has completed a series of clutch throws.
An excellent performance on Sunday will validate the claim he made before this season that he is an "elite quarterback."
San Francisco quarterback 49ers Colin Kaepernick, left, speaks with Atlanta Falcons quarterback Matt Ryan during the second half of the NFL football NFC Championship game, Jan. 20, 2013, in Atlanta.
While Flacco is a traditional-style, drop-back quarterback, the 49ers' Colin Kaepernick is more versatile with superb passing and dynamic running skills. He is one of several quarterbacks who are revolutionizing the NFL with their multi-dimensional ability.
Now in his second year in the NFL, Kaepernick became a starter midway through the current season and has guided his team to a 7-2 record, including a pair of postseason victories. In his nine starts, he has 13 touchdown passes and only four interceptions, and has rushed for more than 500 yards.
San Francisco 49ers head coach Jim Harbaugh (R) and his brother, Baltimore Ravens head coach John Harbaugh, speak during their joint press conference ahead of the NFL's Super Bowl XLVII in New Orleans, Louisiana, Feb. 1, 2013
Sunday's contest is a family affair. For the first time in the four major U.S. professional sports leagues -- hockey, basketball, baseball and football -- brothers are opposing each other as head coaches in a playoff game.
Baltimore's John Harbaugh and San Francisco's Jim Harbaugh are two of the best in the business.
In five seasons with the Ravens, John has compiled a 62-30 record including an 8-4 mark in the playoffs. He has coached the Ravens to three championship-game appearances in their conference.
Jim, a former quarterback in the NFL, has a 27-9 record in two seasons in San Francisco. His 49ers have been to their conference championship game both years.
The Harbaughs have tried to play down their sibling rivalry, but their family connection has been hard for media to avoid. Their father, Jack Harbaugh, coached for decades in a variety of roles mostly in college football.
Last season, the Ravens beat the 49ers, 16-6, when the Harbaugh brothers opposed each as coaches for the first time.
Baltimore Ravens inside linebacker Ray Lewis speaks to journalists during Media Day for the NFL's Super Bowl XLVII in New Orleans, Louisiana Jan. 29, 2013.
Then there's Ravens superstar linebacker Ray Lewis, who announced recently that he would retire at the end of this season. One of the most dominant players in his 17-year NFL career, he has made a phenomenal 13 Pro Bowls, the league's all-star game. He is certain to be a first-ballot inductee into the Pro Football Hall of Fame upon eligibility.
But Lewis has a criminal record. He was indicted on murder and aggravated assault charges due to an altercation after the Super Bowl in 2000. He pled guilty to obstruction of justice in exchange for testimony against two other defendants. He has since worked to reshape his image in part by speaking publicly of his devotion to God.
Also, a U.S. media report this week Sports Illustrated
linked Lewis with a product that contains a substance banned by the NFL. The report said Lewis had requested the product, known as deer antler spray, in hopes of speeding his recovery from an injury he suffered in October. Questioned by reporters in New Orleans, Lewis denied using the substance and said the source of the report "has no credibility."
In addition, the 49ers are hoping to tie the Pittsburgh Steelers for the most wins in Super Bowl history with six. The Ravens are vying for their second Super Bowl victory. They won their first one in 2000, their fifth season in the league.
The American television network CBS is broadcasting the game, which kicks off at 6:30 p.m. local time on Sunday. Multimillion-dollar commercials will air during the broadcast.
Recording artist Beyonce walks offstage after the halftime show press conference ahead of the NFL's Super Bowl XLVII in New Orleans, Louisiana, Jan. 31, 2013.
American pop singer Beyonce' will be the featured performer during the game's halftime show. She was involved in her own controversy this week when she admitted lip-syncing the U.S. national anthem at the inauguration of President Barack Obama last month. But she proved her vocal prowess by singing the national anthem at a Super Bowl news conference on Thursday.
The Ravens and 49ers will prove their worth on Sunday, as well.