In the United States, the inauguration of a new president is one of the nation's biggest ceremonies.

Military officials plan the event using a 12-by-18 meter map of Washington, DC. The map is so big, it is shown in a large building called the DC Armory.

Officials from across the country have gathered at the armory to plan the 58th presidential inauguration.

Lucas Hernandez is part of that group. He works for the United States Marine Corps.

"It's a lot of moving parts. We've got a fairly condensed space where we're working on the Capitol grounds in a fairly short amount of time where we have to get all of these events done and completed in basically what's a no-fail mission that day."

Aaron Lovely works for the United States Army. He says he looks forward to working with other parts of the government on the event.

"We're actually thrilled as the military to have the cooperative partnerships of the other federal agencies that we get to work with in the city, because we're moving a lot of people through a lot of people."

Malik Freeman, who also works for the U.S. Army, says soldiers from all over the country will take part.

"We have almost 7-8,000 soldiers coming from 40 states, so we have to ensure that we get them here, move them forward to their mission site, perform their mission on Inauguration Day, and get them back home within that 72-hour window."

The weather also can be a concern. It is almost always very cold in Washington in January. Michelle Watson, who works for the Coast Guard, says that means planners must ensure that troops are not outside for very long.

"You don't want to keep the military members out there longer than they have to be."

Inauguration Day is Friday, January 20. Because of the disputed election, officials are planning for a complex inauguration and many protesters. They know their plans may change during the day.

Thousands of members of the National Guard will be given the power to detain any protesters who break the law. One of the largest crowds gathered to attend President Barack Obama's first inauguration in 2009. But, officials say, the troops did not make any arrests that year.

Major General Bradley Becker is the commanding general of the Joint Force Headquarters-National Capital Region. He says the biggest concern for organizers is the number of possible protesters.

More than 12 protest marches are planned during the weekend following the inauguration.

On one group's Facebook page, about 150,000 people have said they will be protesting. About 240,000 have said they are interested in doing so.

Many groups also are expected to come to Washington to support the new president, Donald Trump. One of them is called "Bikers for Trump." They have planned gatherings throughout the country in the weeks before the inauguration. They also plan to ride their motorcycles through the city on Inauguration Day.

Stephen Fuller is a professor and faculty chair at the Center for Regional Analysis at George Mason University. He believes at least 200,000 people will attend inaugural events. And he says as many as one million protesters may come to the city on the day Trump takes office or the day after.

Fuller says local and federal officials will be able to deal with the large number of protesters. He says one of the biggest security difficulties of the day will be guarding the president-elect.

By comparison, guarding the protesters will be much easier, Fuller says.

I'm Jill Robbins.

VOA Correspondents Arash Arabasadi and Esha Sarai reported this story from Washington. Christopher Jones-Cruise adapted their reports for Learning English. Mario Ritter was the editor.