General fact: 688 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 688 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 688 is an unremarkable number.
Historical date: November 18th is the day in 1865 that Mark Twain's short story The Celebrated Jumping Frog of Calaveras County is published in the New York Saturday Press.