WASHINGTON – President Barack Obama has been looking to historians for guidance on how to shape his second inaugural's words into a speech for the ages, eager to make good use of his twice-in-a-lifetime opportunity to command the world's attention.

He will take the oath of office Sunday in an intimate White House ceremony witnessed by family, and then again Monday at the Capitol before a crowd of hundreds of thousands on the National Mall. Washington will also play host to the traditional inaugural parade and formal balls Monday, as well as a day of service today that kicks off the festivities.

But it's Obama's inaugural address that will be the centerpiece of the three-day affair. The president will seek to turn the page on a first term consumed by economic turmoil and set an optimistic tone for four more years that will help define his legacy.