math_fact: 1899 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
trivia: 1899 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: March 13th is the day in 1991 that the United States Department of Justice announces that Exxon has agreed to pay $1 billion for the clean-up of the Exxon Valdez oil spill in Alaska.