There was a smile, a wave and a even a short, sharp salute to the military officials greeting him. Donald Trump had clearly been practicing.

America’s President-elect flew into Washington, ready and apparently eager to assume office. Whether America, and the rest of the world, is quite so ready for him, remains to be seen. Certainly the city is taking security seriously – with more than 900,000 people, both protesters and those celebrating, set to arrive in the city for Mr Trump's inauguration.

“The mood around the city was just so celebratory during Obama’s inauguration,” said Heidi Batchelder, a DC school teacher, who said she would simply follow events on the radio and miss the parade. “In our school, the mood has been sombre since the election – amongst our students, amongst the faculty – so it’s just been a very different experience. It feels like this cloud has descended.”

Mr Trump and Melania Trump had a busy schedule on the day before inauguration (AP)

Eric Robertson, a retiree from from Bedford County, Pennsylvania who voted for Mr Trump, was a lot more upbeat. He had come to the capital with his partner, Laurie Taylor.

“Now that we have the free time, I told her, ‘Let’s just go’,” he said. “We were more than thrilled when he won and we both voted for him. And that’s why we’re here.”

Police cars lined much of Pennsylvania Avenue, the parade route for Friday, as workers unloaded crowd control fences from flatbed trucks, erected barricades and marked off pavement with tape.

US Department of Homeland Security Secretary Jeh Johnson said police aimed to keep groups separate, using similar tactics as employed during last year's political conventions.

"The concern is some of these groups are pro-Trump, some of them are con-Trump, and they may not play well together in the same space," Mr Johnson said on MSNBC.

About 30 groups totaling 270,000 people have received permits to stage demonstrations, both for and against the New York businessman in Washington around the inauguration. That number includes some 200,000 people who police say they expect to attend Saturday's Women's March on Washington, an anti-Trump protest. Mr Johnson estimated the number of demonstrations between Friday and Sunday could reach nearly 100.

About 28,000 security personnel, miles of fencing, roadblocks, street barricades and dump trucks laden with sand are part of the security cordon around 3 square miles (almost 8 square km) of central Washington. The dump trucks and buses will block large gatherings of pedestrians with Mr Johnson saying that lessons were taken from recent extremist attacks in France and Germany – although there was no "specific, credible threat".

Security for events over the weekend and associated costs will run into tens of millions of dollars with some estimates saying it could reach $100m (£81m) . Washington DC is expected to spend $30m, with $19m of that expected to be reimbursed by Congress. Those attending the inauguration ceremony and parade will face six security checkpoints, with more than 40 items banned – including backpacks and selfie sticks. However, keeping an eye on the weather forecast for Inauguration Day, the National Park Service announced that it was easing its “no umbrella” policy for Friday, allowing collapsible umbrellas along the parade route and on the National Mall.

Airspace restrictions will also be tightened, with security officials particularly keeping an eye out for small drones, one of the other items that has been banned.

According to the latest polls, Mr Trump may be the most unpopular incoming President for four decades. Progressives, minorities, members of the LGBT community and, of course, those who voted for Hillary Clinton, may be alarmed and fearful as to what is to come in the days and weeks ahead. But for all their noise and protest, for all their petitions and marches, there is nothing they can do. As of noon on Friday, Donald Trump will become the 45th president of the United States, and the world will have a new sheriff-in-chief.

Those protests began in New York on Thursday evening – around 1,000 people turned out for a protest at the Trump International Hotel and Tower, a few streets from the Trump Tower where the businessman lives.

Mayor Bill de Blasio, a Democrat, was among a number of people set to speak at a rally condemning Mr Trump's policies. “Donald Trump may control Washington, but we control our destiny as Americans,” Mr de Blasio said. “We don't fear the future. We think the future is bright, if the people's voices are heard.”

Every presidential inauguration has its own sense of magic, or sense of foreboding, depending on one’s political views. But beyond that, each is a marker in history, a time capsule, a signifier of where the country is, or where it was.

The inauguration of Barack Obama eight years ago, told us that for all its bitter history of racism and bigotry, the country – still struggling fitfully with such issues – was at the point where it could elect its first African American President.

The inauguration of the 70-year-old Mr Trump, the oldest person to take the office, tells us something too. Namely, that more than 60 million Americans felt desperate enough, or anxious enough, or else hated Ms Clinton enough, to take a chance on a man with no political or governing experience. Indeed, for many who threw their support behind the man previously best known to the world as the host of The Apprentice, his lack of political experience and avowed willingness to shake up Washington, was the very attraction.

A man who gave his name as Jim, a construction industry employee who was visiting from St Louis, said he believed there would be a huge turn out, despite reports to the contrary.

“There seems to be a lot of press regarding the Democratic position,” said Jim, who voted for Mr Trump.

Donald Trump's inauguration: What actually happens?

“But if you look at the amount of people who voted Trump in, its not as if it was some small minority. It was a large group of society. I think a large group of society will show up and support him in the inauguration.”

He added: “I think we really got our work cut out for us as a country. We got some internal repairing to do. I hope that he and the cabinet that he selects can do that.

“I hope the mainstream media can make some corrections itself. I really hope some of our mainstream media can stop looking at things with such a bias – and be reporters and kind of tell the whole story and not the side of the story that their chiefs want them to report.”

Mr Trump has set himself an ambitious pace to get results. Within his first 100 days, he wants to reduce environmental regulations he believes are hampering heavy industry, confirm a new Supreme Court Justice, kickstart a billion-dollar infrastructure project and get rid of Obamacare.

Mr Trump had a busy schedule on Thursday alone, his last day as a normal citizen, if the billionaire tycoon can be described thus. That included laying a wreath at Arlington Cemetery, visiting the Lincoln Memorial for a concert featuring Toby Keith, Lee Greenwood and 3 Doors Down, and then being the guest of honour at a formal dinner.

He and Melania Trump, the incoming First Lady, first attended a luncheon to honour Republican leaders. It was held at the Trump International Hotel, located just a few steps from the White House.

Before the media was asked to leave, it filmed Mr Trump thanking this cabinet nominees and claiming they had the highest collective IQ of any incoming administration.

Mrs Trump also said a few words. “It’s great to be here. Thanks for your support. Tomorrow we will start the work to make America great again.”

At the celebratory evening concert on the steps of Lincoln Memorial Mr Trump said: “It's a movement like we've never seen anywhere in the world”.

“You're not forgotten any more. You're not forgotten any more,” he told supporters.