The Power of Twelve

There are:

12 inches in a foot
12 months in a year
12 grades in the American school system
12 signs of the zodiac
12 items in a dozen
12 pence in a shilling
12 people on a jury
12 districts in the U.S. Federal Reserve bank system
12 tribes of Israel
12 apostles in Christianity, which borrowed the idea from
12 apostles in Mithraism
12 labors of Hercules, imposed as punishment
12 days to the Christmas season, from Yule to Epiphany
12 steps to humility (St. Benedict, 520 A.D.)
12 steps of pride (St. Bernard of Clairveaux, 1130 A.D.)
12 steps to sobriety (Bill Miller, founder of AA, 1937)
12 parts to the Boy Scout Law (Trustworthy, loyal, etc.)
12 tones in the chromatic musical scale
12 bars in standard blues music
12 animals in the Chinese cycle of years (rat, ox, tiger, etc.)
12 times 2 = 24 hours in a day
12 times 5 = 60 minutes in an hour
12 times 30 = 360 degrees in a circle
12 times 10 = 120 beats per minute, the standard military marching pace
12 times 10 = 120, the optimum systolic blood pressure
12 volts in automobile electrical systems
12 was the base for early mathematics
12 chairs in the Mel Brooks movie based on a Russian folk tale
12 Monkeys, another movie, by Terry Gilliam
12 Years a Slave, a book and a movie
12 strands in a DNA sequence
Finally, the atomic weight of carbon, the base of all life forms on earth, is 12.01