general_fact: 30 is the percentage of methane on Earth produced from the flatulence of domesticated cows.
math_fact: 30 is a primorial and is the smallest Giuga number.
trivia: 30 is the number of tracks on The Beatles' eponymous album, usually known as The White Album.
historical_date: January 30th is the day in 1667 that the Polish-Lithuanian Commonwealth cedes Kiev, Smolensk, and left-bank Ukraine to the Tsardom of Russia in the Treaty of Andrusovo.