Through the clear, cool morning, crowds of people began descending on the nation’s capital Friday to celebrate, protest or simply witness the inauguration of the most unconventional president-elect in modern American history, Donald John Trump.

At noon, the Republican real estate mogul will take the oath of office and become the 45th commander in chief of the United States, capping a campaign that galvanised millions of Americans who were eager to embrace a Washington outsider willing to say, or tweet, whatever is on his mind. Trump - who has never before held elected office - was jubilant Friday morning before attending a service at St. John’s Episcopal Church and sharing tea with President Obama and First Lady Michelle Obama at the White House.

But his inflammatory rhetoric has angered and offended millions of others, making the 70-year-old New Yorker the most unpopular incoming president in at least four decades. Friday, the stark national divide was already on full display as Trump supporters and detractors began coming face to face on the National Mall, around the White House and throughout downtown D.C.

After almost two hours of delays, the security gates at 7th and Independence Avenue opened to cheers from the restless crowd.

“Trump! Trump! Trump!” a number of them began to shout. Admiring the Capitol building on their way to inauguration, two teachers from Gainesville, Fla., were decked out in bright red coats, fuzzy red earmuffs and buttons with Trump’s face.

One of them, 71-year-old Donna Lutz, said she’d lost friends over her support for Trump.

“For the first time in my life, I have not been able to have an opinion,” she said. “I was very passionate, so now I get to see that my passions were shared.”

But her feelings certainly weren’t shared by everyone.

At John Marshall Park’s checkpoint, Black Lives Matter protesters - chanting “Shut it down” - did just that. Five men chained themselves together, preventing anyone from passing and forcing police officers to redirect attendees to other entrances.

“It feels great that we closed the checkpoint,” said 28-year-old Aaron Goggans, one of the organisers. “But we know this is just the beginning.”

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At the 10th and E streets in downtown Washington, protesters blocked the entrance to another checkpoint.

A group of women tied themselves together with purple yarn and sat on the ground to prevent people from passing through.

“Hey, hey, ho, ho! Donald Trump has to go!” the group of about 100 mostly young protesters. “End white supremacy!”

Armed with signs, brass instruments and life-size wooden crosses, the assembly danced, blew whistles and sang peacefully along with a small marching band.

The protest continued until a large group of inauguration attendees - many dressed in suits and dress clothes - tried to push through the human barricade. People starting falling to the ground and swearing until police officers helped create a lane for the attendees to pass through.

Throughout the city, other anti-Trump protests popped up.

At 14th and I streets NW, about 100 anti Trump marchers chanted, ‘Whose streets? Our streets!”

One man carried a bundle of American flags over his shoulder.

“It’s not enough to continue shouting into the echo chamber of social media,” said Clara Mystif, 31, a writer from Florida. “We’re here to actually put our bodies on the line in support of our friends who are going to be targeted by this regime.”

Still, just before 9 a.m., D.C. police reported several skirmishes at various checkpoints - including one that prompted officers to use pepper spray - but said no one had been arrested throughout the morning.

“So far, so good,” said interim D.C. Police Chief Peter Newsham, adding visitors “will see people with views that are different than yours. We are used to that. When it comes to breaking the law, that’s something we do not tolerate.”

Law enforcement is prepared to contend with more than 60 demonstration groups that plan to gather in the District, including DisruptJ20, which expects at least 30,000 participants. The activists’ website promised “a series of massive direct actions that will shut down the Inauguration ceremonies and any related celebrations.”

To do that, however, they’ll have to overcome a security plan that’s taken months of planning and millions of dollars to execute. Among the obstacles facing any would-be agitators: Checkpoints, roadblocks, truck-barricaded streets, hundreds of Jersey barriers, miles of fencing and 28,000 security officials deployed across 100 square blocks in the heart of Washington.

On Thursday night, hundreds of protesters clashed with law enforcement outside the National Press Club, where a thousand Trump supporters- including a number of infamous online trolls who campaigned for the new president - had gathered for the “DeploraBall.” In the street, demonstrators waved signs, chanted, shouted obscenities and set fires. One man who appeared to be a Trump supporter was struck in the head and left bleeding before police escorted him to safety. Several times, officers directed a chemical spray into the crowd and one person was arrested and charged with conspiring to commit violence.

On Friday, protesters may be confronted by counter-demonstrators who have come to support their new president - most notably, Bikers for Trump, a group that served as a vigilante security force at the Republican National Convention and expects 5,000 members in Washington Friday.

The region’s normally packed Washington-bound Metro trains were mostly empty early Friday. In a yellow line car headed south, two groups of four wearing Trump gear - beanies saying “Trump America’s 45th president” and American flag scarves - sat ebulliently at the end.

One bearded man in a North Face vest and sweatpants, clearly new to Metro, propped his feet on a divider and later asked if he could smoke his cigarette. He hopped off his seat to record a selfie video with his friends.

“It’s the best day in America,” he beamed.

The man swivelled the camera to show the rest of the crowd.

“Washington sucks,” he bellowed, before turning the camera off.

“I said ‘Grab them by the p—y,’ 17 times yesterday,” he joked later, referring to Trump’s vulgar comments on the set of Access Hollywood in 2005. He casually repeated the phrase several times, until his female companion shushed him.

“Today’s a huge day,” he said as the train approached their stop.

“Yuuuuge!” his friend responded.

Meanwhile, on Twitter, a number of elected officials shared messages of thanks for President Obama’s eight years of service.

Despite Trump’s reputation as a showman, the celebration in honuor of the former “Apprentice” star will likely be smaller than the one in 2009 for the nation’s first African American leader.

Trump’s 3pm parade is expected to last just 90 minutes. Obama’s took more than four hours. Trump is expected to appear at three official balls. Obama attended 10. Just 450 bus permits had been sought for Friday. About seven times that many – more than 3,000 – registered eight years ago.

Though Trump suggested “record numbers” of people would attend Friday’s festivities, at least one longstanding ball had to cancel due to a lack of interest, and others have struggled to sell tickets. Compared to past celebrations, far fewer notable celebrities and musicians are attending or performing, and a number of the city’s great halls haven’t been rented.

Trump Inauguration protests around the World Show all 14 1 /14 Trump Inauguration protests around the World Trump Inauguration protests around the World Activists from Greenpeace display a message reading "Mr President, walls divide. Build Bridges!" along the Berlin wall in Berlin on January 20, 2017 to coincide with the inauguration of Donald Trump as the 45th president of the United State Getty Trump Inauguration protests around the World An activist holds up a sign at the "We Stand United" rally on the eve of US President-elect Donald Trump's inauguration outside Trump International Hotel and Tower in New York on January 19, 2017 in New York Getty Trump Inauguration protests around the World Protesters burn a U.S. flag and a mock flag with pictures of U.S. President-elect Donald Trump outside the U.S. embassy in metro Manila, Philippines Getty Trump Inauguration protests around the World Filipino protestors hold placcards during a protest rally in front of the US embassy in Manila, Philippines, 20 January 2017. On the eve of President-elect Donald Trump's inaguration as the 45th president of the United States, Filipinos and Fil-Americans held a protest in front of the US embassy in Manila to denounce the incoming US president. Getty Trump Inauguration protests around the World Hong Kong police officers and security guards look on as an anarchist protester belonging to the Disrupt J20 movement sits after using a heavy duty D-lock and motorcycle lock to chain himself to a railing at the entrance gate to the Consulate General of the United States of America in Hong Kong to protest the inauguration of United States President-elect Donald Trump, Hong Kong, China, 20 January 2017. Two activists were arrested and taken away by Hong Kong police during the demonstration. Getty Trump Inauguration protests around the World A banner is unfurled on London's Tower Bridge, organised by Bridges Not Walls - a partnership between grassroots activists and campaigners working on a range of issues, formed in the wake of Donald Trump's election, which aims to build bridges to a world free from hatred and oppression. Getty Trump Inauguration protests around the World Protesters chain themselves to an entry point prior at the inauguration of U.S. President-elect Donald Trump in Washington, DC, U.S. Getty Trump Inauguration protests around the World Bridges Not Walls banner dropped from Molenbeek bridge in Brussels, Belgium, 20 January 2017, in an Greenpeace action part of protests Wolrd protest in solidarity with people in the US, the day Donald Trump sworn in as the 45th President of the United States. Getty Trump Inauguration protests around the World A woman holds an anti-U.S. President-elect Donald Trump placard during a rally in Tokyo, Japan, Getty Trump Inauguration protests around the World A Palestinian protester holds a placard during a demonstration against the construction of Jewish settlements in the occupied West Bank and against US President-elect Donald Trump, on January 20, 2017, near the settlement of Maale Adumim, east of Jerusalem Getty Trump Inauguration protests around the World Banners on North Bridge in Edinburgh as part of the Bridges Not Walls protest against US President Donald Trump on the day of his inauguration Getty Trump Inauguration protests around the World Russian artist Vasily Slonov (L) and his assistant carry a life-sized cutout, which is an artwork created by Slonov and titled "Siberian Inauguration", before its presentation on the occasion of the inauguration of U.S. President-elect Donald Trump, in a street in Krasnoyarsk, Russia Getty Trump Inauguration protests around the World A woman holds a banner during a march to thank outgoing President Barack Obama and reject US President-elect Donald Trump before his inauguration at a park in Tokyo, Japan, 20 January 2017. EPA Trump Inauguration protests around the World Palestinian demonstrators protesting this week against a promise by Donald Trump to re-locate the US embassy to Jerusalem Reuters

D.C.’s Trump International Hotel, which the new president will pass during his parade, has frequently been targeted by protesters in recent months. An extra layer of high metal fencing appeared outside its front doors this week, and staff have carefully monitored everyone coming and going.

Washington’s lack of enthusiasm for Trump’s arrival may be due in part to the adversarial relationship he’s long had with the fiercely liberal capital, a place he described as a “swamp” that needs draining.

Just 4 percent of D.C.’s residents voted for the man who’s about to move into the city’s most hallowed quarters: 1600 Pennsylvania Avenue.