TIL that the FBI once sent Martin Luther King Jr. a threatening letter encouraging him to commit suicide.
TIL that MLK day wasn't officially celebrated by all 50 states until 2000 even though it's been a federal holiday since 1983.
TIL That from 1906-1920, there was a movement in the US to remove all silent letters and irregular spellings from the English language (eg: although->altho), funded by Andrew Carnegie and supported by Teddy Roosevelt
TIL of Jerrie Cobb, who started flying at age 12 and later set world records for distance flight, speed, and altitude. She played semiprofessional softball to help finance her aviation, ranked in the top 2% of all astronaut candidates, and pioneered humanitarian flights earning a Nobel nomination.