It's the end of a journey that began two years ago, when a black one-term senator from Illinois launched a long-shot run for president, and the beginning of a new era in American politics.
With as many as 2 million people expected to crowd the National Mall - and millions more watching from home - Barack Hussein Obama will be sworn in today as the 44th president of the United States.
It will be a moment rich with symbolism. The election of Obama is an inspiration to millions across the country and around the world that the American dream can be real.
The elaborate ceremony also marks the changing of the guard after eight years of Republican leadership and amid high anxiety about the economy and the future. The stakes for Obama are high.