Seventy-five years ago, the world blew up in just six months. World War II ostensibly started two years earlier, when Germany invaded Poland. In truth, after the rapid German defeat of Poland in September 1939, the conflict was mostly confined to Western Europe for nearly the next two years.

On July 8, 1853, Commodore Matthew C. Perry sailed into Tokyo Bay with four ships to deliver a letter from U.S. President Millard Fillmore proposing peaceful commercial relations. The Japanese refused to accept the letter, until Perry made it clear that this would result in a cannonade from his ships that would have devastated downtown Tokyo.

Between June 29 and July 4, 1913, some 53,000 Union and Confederate veterans of the Civil War gathered at Gettysburg, where many had shot and bayonetted each other fifty years earlier. They embraced—often tearfully—dressed in Blue and Gray, surrounded by the flags under which each side had fought. President Woodrow Wilson told them, “We have found one another again as brothers and comrades in arms, enemies no longer, generous friends rather, our battles long past, the quarrel forgotten—except that we shall not forget the splendid valor.”