Video above: President Trump reacts to letter former President Biden left him in the Resolute desk.

(NEXSTAR) When the incoming and outgoing presidents are attending the former’s inauguration, staffers back at the White House are faced with a massive undertaking: Move one president out and another in, in just a matter of hours.

That’s what happened Monday, as President Donald Trump was being inaugurated. As soon as he and President Joe Biden began their limousine ride to the Capitol, the changeover began.

“As soon as they leave, the executive residence staff swings into action,” Matthew Costello, chief education officer of the White House Historical Association, said during a recent online program about Inauguration Day history. “Essentially, staff is working nonstop to inventory, process and move all of the personal items of one first family out and a new first family in.”

While most Americans don’t get to see every inch of the White House and the changes that are made between first families, we do get to see the Oval Office.

Every president gets to select how the office looks, from the carpet to the artwork on the wall.

The incoming president can keep any of the features already in place from the outgoing president (Trump appears to be keeping several), but most turn it into their own space.

He has kept the Resolute Desk, which all but three presidents Lyndon B. Johnson, Richard Nixon, and Gerald R. Ford have declined to use since it was gifted to President Rutherford B. Hayes by Queen Victoria in 1880.

He also kept a bust of Martin Luther King Jr., which former President Joe Biden also featured in the office, according to the Wall Street Journal.

Like others before him, Trump has photos of his family behind him. In the image below, you can see some of those photos, including one of his mother.

On the opposite side is a display of challenge coins, which are traditionally used by those in the military or Defense Department to signify units, offices, special events, anniversaries, and more.

Biden had a slew of challenge coins on display in the private dining room.

Trump has brought back many of the artwork and adornments that appeared in the Oval Office during his first term.

His iconic “Diet Coke button” is back, per the Wall Street Journal. (WSJ was given an exclusive tour of the Oval Office on inauguration day.) Trump has also brought back a bust of Winston Churchill, which Biden had removed.

Portraits of George Washington, Alexander Hamilton, and Thomas Jefferson are back above the fireplace. (Biden had five portraits hanging over the mantel: a larger portrait of Franklin D. Roosevelt, flanked by smaller versions of Washington, Abraham Lincoln, Alexander Hamilton, and Jefferson). Atop the mantel now sit silver eagle figures, WSJ reports.

Back also is a portrait of President Andrew Jackson near the Resolute desk, which Biden had replaced with a portrait of Benjamin Franklin. Trump decided to keep the portrait of Franklin, according to WSJ.

Trump also ditched a bust of Robert F. Kennedy that Biden had and brought in “The Bronco Buster” sculpture by Frederic Remington (another Remington piece, “The Sergeant,” was featured in a model of the Oval Office at the Republican National Convention over the summer).

A quick scan of the Oval Office appears to show the return of flags for every service branch, which Biden did not have during his term.

Biden, who had kept the drapes from Trump’s first term in the Oval Office, replaced a pastel rug with a dark blue one that his brother, James, selected for him. Trump has brought back the pastel rug.

It’s possible the Oval Office decor will be tweaked or replaced during Trump’s term. As WSJ reports, it was “refreshed” a few months into his first term.

The Associated Press contributed to this report.