During the Civil War, a young Robert Todd Lincoln (left) was traveling by train from New York to Washington during a break from his studies at Harvard. He hopped off the train during a stop at Jersey City, only to find himself on an extremely crowded platform. To be polite, Lincoln stepped back to wait his turn to walk across the platform, his back pressed to one of the train's cars.
This situation probably seemed harmless enough until the train started moving, which whipped Lincoln around and dropped him into the space between the platform and train, an incredibly dangerous place to be.
Lincoln probably would have been dead meat if a stranger hadn't yanked him out of the hole by his collar. That stranger? None other than Edwin Booth, one of the most celebrated actors of the 19th century and brother of eventual Lincoln assassin John Wilkes Booth.
Lincoln immediately recognized the famous thespian—this was sort of like if George Clooney pulled you from a burning car today—and thanked him effusively. The actor had no idea whose life he had saved until he received a letter a few months later commending him for his bravery in saving the President's son.