Donald Trump promised to act with "historic speed and strength" when he entered the oval office and by the time he completed his first 24 hours in the job, he delivered on that pledge.
Shortly after his swearing in as the 47th president, the Commander-in-Chief broke from the normal conduct of incoming presidents and swiftly began enacting his vision for his second term.
Armed with his signature black marker and trademark bluster, Trump issued nearly 1,600 pardons and signed dozens of executive orders that rolled back many of the signature policies of his predecessor.
Some of those measures included blocking a federal law banning social media platform TikTok, ending diversity and inclusion programs across the federal government, and seeking to end an immigration practice known as birthright citizenship.
The speed of Trump's actions took many by surprise. On day one, he signed almost 50 executive actions.
For comparison, when the president took office in 2017, he signed just one executive order on Inauguration Day.
"It is a fire hose right now. That's what he does. He creates a tonne of chaos so it's hard to keep up with it," said lawyer and Texas Democrat Jasmine Crockett.
"Everything is overload."
Along with the flurry of executive actions, Trump's first full day in office featured a pointed sermon, a "nice" letter from Biden and the release of January 6 prisoners.
But a series of speed bumps lie ahead, threatening to slow the 47th president's lightning pace and derail his ambitious, "shock and awe" agenda.
US media is reporting that opponents, scholars and other groups believe Trump's actions have already exceeded the limits of his presidential power.
After eclipsing his first week record of executive actions, Trump is facing an extensive list of legal challenges to his orders. Experts believe some issues could drag on in court battles for years.
These were the key takeaways from day one.
Biden left Trump an 'inspirational type' letter
Sitting at the Resolute Desk inside the Oval Office, Trump was settling into his new role and taking questions from reporters when he was asked about a treasured presidential custom.
Since Ronald Reagan's presidency, it has been the tradition of departing presidents to write a note to their successor and leave it in the desk drawer.
The letters typically include warm congratulations, warnings and advice on how to navigate America's highest office.
Trump maintained the tradition when he handed over to Biden in 2020 despite his refusal to follow other conventions, such as attending the inauguration ceremony. Biden described the note as "very generous".
On Monday, a reporter asked the president if Biden had continued the custom and left him a letter.
Trump responded by opening the drawers of the Resolute Desk and pulling out an envelope with the number "47" scrawled on the front.
He joked about reading it with the gathered press, but quickly added he would check it first.
Later, he told reporters he appreciated the note, offering few details on what was included.
"It was a little bit of an inspirational-type letter, you know, enjoy it, do a good job. Important, very important, how important the job is. But I may, I think it was a nice letter, I think I should let people see it," he added.
Biden has declined to say what he wrote, noting "that's between Trump and me".
'Have mercy': Bishop makes pointed sermon in front of Trump
Trump started his first full day as America's commander-in-chief by attending a prayer service at the Washington National Cathedral.
The Episcopal bishop of Washington, Right Reverend Mariann Edgar Budde, delivered her sermon as part of the interfaith ceremony.
But she surprised everyone when she made a direct plea to the president.
"In the name of our God, I ask you to have mercy upon the people in our country who are scared now," she said, looking directly at the president.
"There are gay, lesbian and transgender children in Democratic, Republican and independent families. Some who fear for their lives."
Her comments came hours after Trump signed a slew of executive orders, including one that proclaimed the US government will only recognise two sexes, male and female.
She also pleaded with the president to show compassion to undocumented immigrants, as he seeks to end birthright citizenship and halt all refugee admissions.
"The people who pick our crops and clean our office buildings, who labour in poultry farms and meat-packing plants, who wash the dishes after we eat in restaurants and work the night shifts in hospitals, they … may not be citizens or have the proper documentation, but the vast majority of immigrants are not criminals," she said.
"I ask you to have mercy, Mr President, on those in our communities whose children fear that their parents will be taken away."
Trump and his vice-president, JD Vance, showed no emotion during the sermon, but did exchange a few whispered words.
When asked for his reaction by reporters, Trump said the sermon was "not too exciting".
"I didn't think it was a good service," he said.
But later, at 12:49am local time, Trump got on the social media platform Truth Social to blast the Right Reverend Budde for her sermon.
"She brought her church into the world of politics in a very ungracious way," he wrote.
"She was nasty in tone, and not compelling or smart."
Within hours, Trump experiences the limits of his power
Hours after he was sworn into office, Trump signed a flurry of executive orders, which he vowed would enact "the complete restoration of America and the revolution of common sense".
Executive orders basically allow presidents to make policy outside of the regular lawmaking process through Congress.
But executive power still has limits, and it can be challenged — and overturned — in the court system.
After Trump signed an executive order to cut off birthright citizenship — the right of any child born on US soil to call themselves an American citizen — 18 Democratic attorneys-general filed a lawsuit.
"The President has no authority to rewrite or nullify a constitutional amendment … nor is he empowered by any other source of law to limit who receives United States citizenship at birth," they said.
Four additional states filed a similar suit later in the day, bringing the total number of states challenging Trump to 22.
New Jersey Democratic Attorney-General Matt Platkin said presidents might have broad authority but they are not kings.
"The president cannot, with a stroke of a pen, write the 14th Amendment out of existence, period," he said.
Elon Musk's Department of Government Efficiency (DOGE) is also facing multiple legal challenges in court.
Trump tapped the richest man in the world to lead DOGE in identifying potential spending cuts and streamlining government regulations.
But public interest groups say the DOGE panel violates laws on transparency for government advisory groups.
No sign of mass immigration crackdown yet
Trump pledged to introduce the largest deportation program in US history once in office and started laying the groundwork for this plan with a series of executive orders signed on day one.
With the sweep of a pen, he halted the use of an app set up by the Biden administration to allow migrants to apply to enter the US legally as asylum-seekers and reinstated the "Remain in Mexico" policy, which forces asylum-seekers to wait in Mexico until they are scheduled to appear before US immigration judges.
He has also prioritised the completion of the border wall.
The orders had an immediate impact. The Associated Press reported that within minutes of Trump being sworn in, migrants who had appointments to enter the US using the special app saw them cancelled.
But other moves were slower to unfold. As of Tuesday evening, local time, there was little sign of the large-scale immigration raids expected to target major sanctuary cities immediately after Trump's inauguration.
US media had reported his team was planning to begin large-scale deportations the day after his inauguration, with suggestions up to 200 officers could be sent to Chicago to carry out a major immigration raid.
Other sanctuary locations under consideration included New York and Miami.
But Trump's "border czar", Tom Homan, said Immigration and Customs Enforcement (ICE) had launched smaller operations the day after the inauguration.
"I wouldn't call them raids, they're targeted enforcement operations," he told CNN.
"I'm not going to tell you specific locations out of safety concerns, but ICE is back doing their job effective today."
Homan said officers are initially targeting undocumented migrants with "a criminal conviction that makes them a public safety threat".
A Trump enemy loses security detail
Within hours of taking office, Trump terminated the Secret Service detail that was assigned to his former national security adviser, John Bolton.
Trump fired Bolton in September 2019 after saying he "strongly disagreed with many" of his hawkish foreign policy positions.
The next year, Bolton published a memoir in which he claimed Trump was woefully ill-informed on foreign policy matters, and claims he personally asked Chinese President Xi Jinping to help him win the 2020 election.
Trump denied the allegations and said Bolton "should go to jail".
But in 2020, after the US assassinated Iranian military officer Qasem Soleimani, American authorities learned of a revenge plot against senior government figures, including Bolton.
He's been under Secret Service protection ever since, but his detail was taken away from him hours after Trump was sworn in.
"I am disappointed but not surprised that President Trump has made this decision," Bolton said in a statement to CNN.
"The Justice Department filed criminal charges against an Iranian Revolutionary Guard official in 2022 for attempting to hire a hitman to target me."
During a White House press conference, Trump called Bolton a "stupid guy" and said no-one should expect a security detail for life.
"I thought he was a very dumb person," Trump said.
"I used him well, because every time people saw me come into a meeting with John Bolton standing behind me, they thought that he'd attack them, because he was a warmonger."
Jan 6 rioters walk free
To the surprise of his opponents and critics, Trump ordered the immediate release of everyone jailed over the January 6, 2021 attack on the Capitol.
The insurrection in Washington DC was widely seen as an attempt by Trump's supporters to prevent the certification of Biden as president.
Trump had said ahead of inauguration day that he would pardon some of the people involved in the riots, but suggested particularly violent offenders might not be freed.
Trump issued full pardons to nearly 1,500 people involved in the attack. Fourteen other offenders had their sentences commuted, and all outstanding charges over the attack were dropped.
Hours later, Oath Keepers extremist group founder Stewart Rhodes, who helped orchestrate the January 6 riot, walked out of prison.
He had been serving an 18-year sentence for seditious conspiracy.
Trump's actions have drawn criticism from police who battled the mob, their families, Democrats and even Republicans.
Michael Fanone, a police officer who was beaten and repeatedly tasered in the insurrection, said he has asked a court for protection in response to the pardons.
"These individuals are not prevented from making contact with me or members of my family, and I anticipate that they will," he told the ABC.
Former House Speaker and Democrat Nancy Pelosi has branded the pardons "an outrageous insult" to the justice system.
"It is shameful that the President has decided to make one of his top priorities the abandonment and betrayal of police officers who put their lives on the line to stop an attempt to subvert the peaceful transfer of power," she said in a statement.
