general_fact: 50972 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 50972 is an uninteresting number.
trivia: 50972 is an uninteresting number.
historical_date: July 22nd is the day in 1793 that Alexander Mackenzie reaches the Pacific Ocean becoming the first Euro-American to complete a transcontinental crossing of Canada.