general_fact: 156 is the number of hourly gongs a clock strikes in one day (78 AM gongs and 78 PM gongs).
math_fact: 156 is a pronic number, a dodecagonal number, a refactorable number and a Harshad number.
trivia: 156 is the number of episodes the TV series The West Wing ran on NBC from 1999 to 2006, including an extra episode.
historical_date: June 4th is the day in 1957 that Dr. Martin Luther King, Jr. delivered his famous Power of Nonviolence speech at the University of California, Berkeley.