general_fact: 715 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 715 is an unremarkable number.
trivia: 715 is an uninteresting number.
historical_date: December 15th is the day in 1997 that a chartered Tupolev TU-154 from Tajikistan crashes in the desert near Sharja, United Arab Emirates airport killing 85.