The assassination of President John F. Kennedy on a sunny day in Dallas, the murder of Medgar Evers as he stood in his Jackson, Miss., driveway, the obliteration by bomb of four little girls in the basement of a Birmingham church and the savage dogs of Birmingham's "Public Safety" director Eugene "Bull" Connor.
Each piece became a part of the puzzle of America's slow acceptance of equal rights for its citizens, regardless of color. Fifty years ago, that acceptance was codified in law through the Civil Rights Act of 1964.
At the University of Texas this week, President Barack Obama and former Presidents George W. Bush, Bill Clinton and Jimmy Carter will join a host of other speakers for a civil rights summit called "We Shall Overcome."
It's an important remembrance for a law that's all but taken for granted now.
Yet in early 1964, there was no certainty that a Civil Rights Act would pass, and certainly not one as ambitious as what ultimately became law.
The momentum was there. The march from Selma, Martin Luther King's "I Have a Dream" speech and the desire to honor Kennedy's legacy were important elements.
But if there was a puzzle master, it was the political and legislative genius that was Lyndon Baines Johnson. Today, Johnson's legacy is as likely to be connected to the Vietnam War as anything else. At worst, he's a caricature, a big brash Texan bullying his way through Washington.
In fact, his work on the Civil Rights Act was a delicate political dance that no one else in the country could have accomplished at that time. Johnson worked Democrats and Republicans. He worked the press. He traded on the budget. He traded on a tax cut. Imagine this: He got liberals and conservatives to work together on what was then a political third rail.
It's appropriate that the Civil Rights Summit will be held at the LBJ Presidential Library. Often, the act is cast as Johnson following up on Kennedy's work. But Johnson was crafting civil rights legislation in the late 1950s and even managed to get a weak bill passed in 1957. That early legislative work paid off when the time came to push the more ambitious act.
On July 2, 1964, at the signing of the act, Johnson recalled the nation's founding principles - that all are created equal and are entitled to the blessings of liberty.
"Yet millions are being deprived of those blessings - not because of their own failures, but because of the color of their skin," he said.
America has not yet resolved its struggle with race and inequality. Work continues every day. But Johnson's political brilliance in 1964 brought the nation a long way toward establishing equal treatment for all.