Donald Trump will mark his first full day as President with a church service and possibly a visit to the headquarters of the CIA.
The new President mixed pageantry and celebrations with practical politics in the hours after being sworn into office.
Immediately after watching a parade outside the White House, photographers and cameramen were invited to see him sign papers confirming his first cabinet appointments.
The pictures show the President had kept his promise to return a bust of former British prime minister Winston Churchill to the Oval Office after Barack Obama moved it to make way for one of Martin Luther King.
Mr Trump's staff have found room for both.
Mr Trump's staff have found room for both.
The President also signed an executive order aimed at "minimising the economic burden" of Obamacare.
The order allows government agencies to delay the implementation of any parts of the Affordable Care Act - Barack Obama's signature healthcare law - which could put a "fiscal burden" on families, states or healthcare providers.
It is the first step in Mr Trump's plans to "promptly repeal" and replace Obamacare, a key promise made during his election campaign, but Republicans in Congress are yet to propose a replacement for the insurance programme.
During his election, Mr Trump campaigned on a detailed 18-point plan of the things he would do on his first day in office.
But since then, he seems to have distanced himself from taking such a rapid-fire approach to implementing policies, especially when it comes to complicated issues, which may involve negotiations with Congress or foreign leaders.
Within minutes of his inauguration as US President, Mr Trump's administration announced plans to develop a "state-of-the-art" missile defence system to protect the US against attacks from Iran and North Korea.
In further measures, Mr Trump's administration said it would reverse cutbacks to the defence budget and "submit a new budget to Congress outlining a plan to rebuild our military".
It added: "We will provide our military leaders with the means to plan for our future defence needs."
As Mr Trump's pledges were published on the newly revamped White House website, references to climate change were deleted and replaced with the President's "America First Energy Plan".
The policy outlines intentions to scrap the "harmful and unnecessary" Climate Action Plan and Waters of the
US rule brought in by Barack Obama.
Also detailed are plans to cut tax rates for workers and businesses, as well as a withdrawal from the Trans-Pacific Partnership trade agreement.
Later, Mr and Mrs Trump will attend a National Prayer Service at Washington Cathedral.
A visit to CIA headquarters at Langley in Virginia was also thought to be on his schedule, but may be postponed because his new CIA Director Mike Pompeo has yet to be confirmed by the Senate.
The visit will receive even closer scrutiny than usual because of Mr Trump's disparaging comments about intelligence officials in relation to allegations that Russian hackers intervened in the election.
Mr Trump began his Presidency by outlining a bleak image of America's current state and promising to improve it by putting the country and its citizens first.
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He said: "From this day forward, it is going to be only America first. America first. Every decision on trade, on taxes on immigration, on foreign affairs will be made to benefit American workers and American families.
"We must protect our borders from the ravages of other countries making our products, stealing our companies and destroying our jobs. Protection will lead to great prosperity and strength."
He was surrounded by former presidents and congressional leaders but castigated their record.
"For too long, a small group in our nation's capital has reaped the rewards of government while the people have borne the cost," he said in his address.
"Washington flourished but the people did not share in its wealth. Politicians prospered, but the jobs left and the factories closed."
His defeated Democratic rival Hillary Clinton listened impassively during the speech but applauded politely at the end.
Later, Mr Trump praised her for attending the inauguration ceremony despite their bitter election battle, saying he was "very, very honoured" that she and former president Bill Clinton attended the ceremony.
Demonstrators were kept away from the official events, but there were several skirmishes between protesters and police. Vehicles were damaged and set alight and more than 200 people were arrested.
Mr Trump ended the day by attending three inaugural balls, dancing with First Lady Melania at each one.
To no one's surprise, the song he chose to dance to was Frank Sinatra's My Way.