This Super Bowl will be filled with firsts and one significant last.
The Harbaughs, San Francisco's Jim and Baltimore's John, will be the first pair of brothers to coach against each other in the NFL title game.
Quarterbacks Colin Kaepernick of the 49ers and Joe Flacco of the Ravens each will be playing in his first Super Bowl where success is the ultimate measure of elite QBs.
It'll be Baltimore's first crack at a championship in a dozen years, San Francisco's first in 18. They are a combined 6-0 in Super Bowls (the 49ers own five of those victories), so one club will lose the big game for the first time.
And middle linebacker Ray Lewis, Baltimore's emotional leader and top tackler, will be playing in the final game of his 17-year career before heading into retirement.
"This is our time," Lewis pronounced.
For all of those story lines, none is expected to command as much attention as Harbaugh vs. Harbaugh. The game in New Orleans on Feb. 3 was quickly given all manner of nicknames: The Brother Bowl. The Harbaugh Bowl. The Har-Bowl. The Super-Baugh.
The Harbaughs' sister, Joani Crean, wrote in a text to The Associated Press: "Overwhelmed with pride for John, Jim and their families! They deserve all that has come their way! Team Harbaugh!"
As John prepared to coach the Ravens in the AFC championship game Sunday night, he watched on the stadium's big video screen as Jim's 49ers wrapped up the NFC championship.
John looked into a nearby TV camera, smiled broadly and said: "Hey, Jim, congratulations. You did it. You're a great coach. Love you."
Less than four hours later, the Ravens won, too. Some siblings try to beat each other in backyard games. These guys will do it in the biggest game of all.
Who's a parent to cheer for?
During the 2011 regular season, the Harbaughs became the only brothers to coach against each other in any NFL game (the Ravens beat the 49ers 16-6 on Thanksgiving Day that year).
CBSSports.com columnist Clark Judge says the brother-vs.-brother storyline for this year's championship match is old, "with people speculating on it a year ago when the brothers finished a game short of the Super Bowl.
"Now that they're in, get ready for a lot of questions of what it feels like," despite pleas from John Harbaugh to "just cut that out. Could we all agree on that? We did that last year, and it got old. . . . We'll pass on that and talk about the two teams."
The NFC West champion 49ers (13-4-1) opened as 5-point favorites, seeking a record-tying sixth Super Bowl title to add to those won by Hall of Fame quarterbacks Joe Montana and Steve Young.
Lewis was the MVP when the AFC North champion Ravens (13-6) beat the New York Giants in 2001.