math_fact: 737 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 737 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: January 6th is the day in 1978 that the Crown of St. Stephen (also known as the Holy Crown of Hungary) is returned to Hungary from the United States, where it was held after World War II.