With America and the entire world expecting with a high level of enthusiasm for him to take office, Barack Hussein Obama has officially become United States’ 44th President.

In his speech, President Obama referred to the problems the United States is facing and called on all Americans to stand united and take greater responsibility not only for themselves, but also for the country and the whole world.

Obama marked the historic moment of becoming the first African-American President of the United States by emphasizing that "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."

President Obama denounced the policies of the past administration and called on U.S. citizens to return to the traditional American virtues of hard work, tolerance and sacrifice. Those virtues were the hard stone which helped America in moments of crisis, the President added.

"So it has been. So it must be with this generation of Americans," Obama said in reference to the ideals of America’s forebears and to its founding documents. He talked about the "new era of responsibility" which begins with his swearing in and that will heal America.

In this new era of responsibility, Americans must think not only of themselves, but at the greater good of the nation. For Obama’s supporters this may also mean accepting some things once thought unacceptable such as working together with the opponents they've long criticized.

Obama ended his speech by underlining the fact that America is still the most prosperous and most powerful nation on the planet, the productivity of its workers is not lower than when the financial crisis began, and the minds of Americans are no less inventive.

"Starting today, we must pick ourselves up, dust ourselves off, and begin again the work of remaking America," the President told a crow of approximately one million people gathered in front of the Capitol.

Obama’s speech was very somber and it did not have lines which begged for roars and applause. The message it delivered was very accurate and articulate. Nevertheless, the speech ended in jubilation.

The day was full with symbolism and historic scent. Barack Obama, the son of a black Kenyan man and a white Kansas woman, moved into the White House, which was built partly by slaves. Obama said the oath holding his hand on the same Bible used by Abraham Lincoln at his inauguration.

However, in his speech, Obama did not elaborate on the historic moment America is witnessing. He left that to others and instead focused his address on the state of the nation. The celebration was sobered a bit by Obama’s evaluation of the state of a country shaken by home foreclosures, shuttered businesses, lost jobs, costly health care, failing schools, energy dependence and the threat of climate change.

The challenges America is facing are “real,” “serious” and “many,” Obama underlined. But although they will not be met easily and it will take time to do it, “they will be met,” the President ended his speech in roars and applause.