At age 16:
Albert Einstein wrote an essay containing the beginnings of the special theory of relativity. In it, Einstein showed that time and motion are relative to the observer.
American sharpshooter Annie ("Annie Get Your Gun") Oakley challenged and defeated the well-known marksman Frank Butler, whom she later married. She could hit a dime in mid-air from 90 feet.
Legendary womanizer and adventurer Casanova was expelled from a seminary for moral misconduct.
Cuban revolutionary Jose Marti had his first arrest and exile.
George McFarland ("Spanky" in the Our Gang series) retired from the movies and spent the rest of his life doing sales and charity work.
Sir Henry Morton Stanley ("Dr. Livingstone, I presume?") sailed for New Orleans as a cabin boy.
Cornelius Vanderbilt began a ferry service between New York City and Staten Island.
Tennis player Tracy Austin became the youngest person to win the U.S. Open.
Guitar player and songwriter Maybelle Carter invented the 'Carter lick,' which used the thumb to play melody and changed the role of the guitar in country music to that of a lead instrument.
American poet and journalist William Cullen Bryant wrote the first draft of his most famous poem, Thanatopsis.
American film director Howard Hawks became a professional car and airplane racer.
Patrick Taylor left home in Beaumont, Texas with only a suitcase full of clothes, 35 cents and the desire to attend college. Evenually he earned a petroleum engineering degree and became one of the richest men in Louisiana.