Super Bowl XLVII: Harbaugh brothers in sibling battle
Super Bowl XLVII will be a family affair as San Francisco 49ers head coach Jim Harbaugh faces his older brother John, who leads the Baltimore Ravens into the match.
Sunday's game in New Orleans will not only be the first time that two brothers coach against each other in a Super Bowl, but also the first time it has happened in the championship game of any major US sport.
Psychologist Katherine Woolf from University College London spoke to the BBC's Zeinab Badawi about whether being a sibling changes the dynamics in a competitive situation like this - and how.
Viewers in the UK can watch Super Bowl XLVII live on BBC Two from 23:00 GMT on Sunday.
Most watched/listened
-
David Beckham's emotional farewell
-
Record breaking demolition of viaduct
-
Gumball rally sets off from Denmark
-
Japan's incredible shrinking building
-
Syria army 'storms' rebel town Qusair
-
Why Texas German is a dying dialect
-
Hadfield 'hit Earth like a car crash'
-
Can jellyfish venom help humans?
-
Plane catches fire on landing in Russia
-
One-minute World News
-
Writing Bible's 788,000 words by hand
-
City lit up after 20 years in dark
-
How do you round up a camel herd?
-
A call from the top of the world
-
Chile coast littered with dead animals
~RS~q~RS~~RS~z~RS~47~RS~)
