The 53 and 1/3 yards separating John and Jim Harbaugh on Sunday as they stand on opposite sidelines at Super Bowl XLVII will seem like an endless emerald expanse compared to the line of tape that divided them in a shared bedroom in Ann Arbor, Mich. during their youth.
Born just 15 months apart, the sons of Jack and Jackie Harbaugh have competed throughout their lives and will take their sibling rivalry to the grandest stage in football: The Super Bowl. Or, better yet, Jim's 49ers and John's Ravens will be competing in the HarBowl.
"I don't know if we had a dream this big. We had a few dreams, we had a few fights. You know, we had a few arguments, just like all brothers," John told reporters after the Ravens clinched a berth in the Super Bowl. "We'll try to stay out of that business. We'll let the two teams duke it out as much as possible."
The eldest brother at age 50, John rose through the coaching ranks during a long career on the NFL sidelines. By contrast, Jim, 49, started in the NFL as a head coach and reached the Super Bowl in just his second season in San Francisco. After a 14-year playing career, the fiery younger brother leads the favored team into the Superdome.
Whatever the sibling rivalry simmers beneath the surface will likely be reinvigorated when one hoists the Lombardi Trophy at the expense of the other. Even so, the Harbaughs are hardly the only notable sibling rivals in sports.
From the Williams sisters to the DiMaggio brothers, here are some of the other notable sibling rivalries in sports: