A roller coaster of emotions gripped politicians, pundits and the American public in Washington, D.C., today as the nation awestruck by the inauguration of the nation's first black president and jubilant about the celebrations to follow turned its concern to the collapse of Sen. Ted Kennedy this afternoon.
As the senator received medical care at a Washington hospital, black and white, young and old, stars and starstruck witnessed history Tuesday as Barack Obama waved to roaring crowds along the inaugural parade route after taking the oath of office to become the nation's 44th president.
Obama's swearing in as the first black president elicited a range of emotions from the throngs of onlookers who flocked to Washington today for the inauguration, the parade and balls that follow.
An estimated 1.8 million people in the nation's capital watched President Obama take the oath of office and deliver his hotly-anticipated inaugural address. As of late afternoon, two senior law enforcement officials said they did know of not a single arrest on the National Mall.
Watch live coverage of the Inauguration all day and go to the Inauguration Guide for all of ABC News' coverage details.
Before the swelling crowd, Obama emphasized that it will be up to people from all walks of life to help bring nations closer together.
"What is required of us now is a new era of responsibility -- a recognition, on the part of every American, that we have duties to ourselves, our nation, and the world, duties that we do not grudgingly accept but rather seize gladly, firm in the knowledge that there is nothing so satisfying to the spirit, so defining of our character, than giving our all to a difficult task," Obama said in his inaugural address.
"This is the price and the promise of citizenship."
Far outside the Beltway, others came together at homes, schools, work places and watch parties across the country and around the world to observe America's transition of power, some celebrating in places as distant as Obama's father's hometown of Kogelo, Kenya.
In the Middle East, television stations aired Obama's inauguration with one notable exception -- Iraq's state-run Iraqiya Television.
Even Pope Benedict sent Obama well wishes today via telegram.
"Under your leadership may the American people continue to find in their impressive religious and political heritage the spiritual values and ethical principles needed to cooperate in the building of a truly just and free society, marked by respect for the dignity, equality and rights of each of its members, especially the poor, the outcast and those who have no voice," the Pope wrote.
"Upon you and your family, and upon all the American people, I willingly invoke the Lord's blessings of joy and peace," he added.
"No triumph tainted by brutality could ever match the sweet victory of this hour and of what it means to those who marched and died to make it a reality," said California Sen. Dianne Feinstein just before the Obama took the oath of office. "Our work is not yet finished, but future generations will mark this morning as the turning point for real and necessary change in our nation."