Barack Hussein Obama today became the 44th president of the United States of America, the first black man to hold the office.
His left hand resting on the same Bible where Abraham Lincoln's rested at his inauguration 168 years ago, Mr. Obama took the oath shortly after the sun reached its highest point above Washington. The crowds were large and enthusiastic, the sun bright, and both defied the cold January air.
Addressing his country as president for the first time, Mr. Obama acknowledged the tall and numerous hurdles the United States faces, but also set lofty goals such as reducing the cost of health care and dependence on foreign oil, and addressing poverty and hunger on a global level.
He called for "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."
This spirit, he said, is "why a man whose father less than 60 years ago might not have been served at a local restaurant can now stand before you to take a most sacred oath."
Mr. Obama also alluded to a change in his approach to homeland security, compared to his predecessor.
"As for our common defence, we reject as false the choice between our safety and our ideals," he said.
The statement was met with cheers and applause and Mr. Obama maintained a steely stare as the noise subsided.
He finished his speech by drawing on the words of George Washington, the first president:
"So let us mark this day with remembrance, of who we are and how far we have travelled. In the year of America's birth, in the coldest of months, a small band of patriots huddled by dying campfires on the shores of an icy river. The capital was abandoned. The enemy was advancing. The snow was stained with blood. At a moment when the outcome of our revolution was most in doubt, the father of our nation ordered these words [written by Thomas Paine] be read to the people: "Let it be told to the future world...that in the depth of winter, when nothing but hope and virtue could survive...that the city and the country, alarmed at one common danger, came forth to meet [it]."
"America, in the face of our common dangers, in this winter of our hardship, let us remember these timeless words. With hope and virtue, let us brave once more the icy currents, and endure what storms may come. Let it be said by our children's children that when we were tested we refused to let this journey end, that we did not turn back nor did we falter; and with eyes fixed on the horizon and God's grace upon us, we carried forth that great gift of freedom and delivered it safely to future generations."
After the ceremony, the new president and the former president descended part way down the stairs of the Capitol, flanked by their wives. Mr. Bush leaned over and made a joke that made his three companions erupt into laughter before boarding his helicopter, Executive One, formerly Marine One, bound for Texas.
As the helicopter took off, the Obamas, now flanked by the Bidens, waved from the Capitol's steps.
They then went on to a luncheon with members of Congress. A parade and 10 official inaugural balls will follow this afternoon.
Earlier this morning, dawn crept over crowds of tens of thousands of people who had gathered in Washington, D.C. as they waited for the inauguration.
They came by rail, on tightly-packed subways cars, and on foot through crowded streets to stake a small patch of grass in the National Mall, or a swath of pavement near the Lincoln Memorial from which to witness history despite wind chills that dragged temperatures to -10 degrees Celsius.
Hundreds of thousands of people flooded the Washington subway system early this morning en route to witness history, and early indications supported crowd predictions of two million or more. Elevators and escalators within the subway system were shut down, allowing the crowds to emerge more safely and steadily onto the streets.
Staking out spots with lawn chairs and sleeping bags, spectators jockeyed for real estate that allowed a view of large-screen televisions that replayed the inaugural concert in which Bruce Springsteen, John Legend and other's performed on Sunday.
Above them armed guards patrolled the roof tops surrounding Capitol Hill, and below them vendors had already began hawking their Obama-themed paraphernalia.
Mr. Obama, his wife, Michelle, started the day with a service at St. John's Episcopal Church near the White House this morning. Accompanied by Mr. Biden and his wife, Jill, their motorcade then dropped them off at the White where they were greeted by Mr. Bush and his wife, Laura.
A short time later, Mr. Bush left the White House as president for the last time. He and Mr. Obama left for Capitol Hill where Mr. Obama was sworn in.
In the minutes before the ceremony, former presidents Jimmy Carter, George H. W. Bush and Bill Clinton were seated on the inaugural platform. They were followed by Malia and Sasha Obama dressed in brightly-coloured winter coats and wide grins.
Mr. Obama arrived to uproarious cheers of "Obama!" that resumed shortly after his inaugural address.
Keeping a White House tradition, Mr. Bush left a confidential note in the Oval Office for his successor to wish him well as his historic presidency begins.
Despite the goodwill both at home and abroad as Mr. Obama takes office he enters the White House with the highest favorability numbers since Jimmy Carter markets worldwide traded lower Tuesday. In the U.S., worries about the financial sector led to a recent drop of more than 150 points in the Dow Jones Industrial Average.