› added 8 years ago

149

TIL Bulletproof vests expire, and most police officers replace their vests every 5 years.

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via ift.tt

6Da7 TIL of a high frequency tone that can only typically be heard by people under 25 years old called the Mosquito tone. Some places use it to deter teenagers from loitering the area.
d6oE TIL that in 1972 some of Aircraft Carrier USS Ranger’s crew carried out two-dozen acts of sabotage to prevent the ship from returning to Vietnam
a8egZ TIL that 31 years after the atomic bombings of Hiroshima and Nagasaki, the pilot of the former flight, Paul Tibbets, re-enacted the bombing in the original plane at a Texas air show, complete with mock mushroom cloud. Japanese diplomats demanded a formal apology for this.
bwQ0 TIL the melody of the American national anthem comes from a drinking song about Greek gods and sex by a British gentleman’s club
4XrMo TIL the monster truck, Grave Digger has had 41 iterations. Number 13 was skipped because of Triskaidekaphobia