They have the red phone that received the first-ever 911 emergency call.

They have the desk J. Edgar Hoover used as FBI director.

And there’s the handcuffs used by a police officer to arrest Sirhan Sirhan, the man who assassinated Sen. Robert F. Kennedy in 1968.

Twenty years in the making, the National Law Enforcement Museum in D.C.’s Judiciary Square is finally opening its doors to the public on Saturday. Fox News was given an early tour of the museum this week, as workers buzzed around the complex making last-minute finishing touches.

CEO Craig Floyd said the purpose of the museum is to not only to honor the law enforcement profession but to give people a greater appreciation for what these officers do across the country.

“People are, hopefully, going to come away with a better understanding and appreciation of the value and the vital role that law enforcement plays in our society,” said Floyd, the founding CEO of the National Law Enforcement Officers Memorial Fund.

LAW ENFORCEMENT MUSEUM OFFERS INTERACTIVE EXHIBITS, COP-SHOW MEMORABILIA, AND A CHANCE TO 'WALK IN THE SHOES' OF OFFICERS

To do that, the museum — which sits across the street from D.C.’s National Law Enforcement Officers Memorial Park — boasts a collection of more than 21,000 artifacts from famous police cases. It also offers "walk in the shoes" exhibits and interactive experiences, aimed at giving visitors a better idea of what law enforcement does.

“We have J. Edgar Hoover’s desk, and so many other artifacts associated with his amazing career as the director of the FBI,” Floyd said. “We have the bullet-proof vest used by Al Capone.”

The museum also has artifacts from more recent events, like the September 11th attacks, the D.C. sniper attacks in 2002, and the 2014 shooting of Michael Brown in Ferguson.

But the museum offers so much more. Its Day in the Life exhibit allows visitors to observe a typical day of patrol officers working on Lake Minnetonka in Minnesota, or in the city of Atlanta, or along the Arizona Highways, allowing guests to fast-forward or rewind through their daily — and often hectic — shifts.

Visitors can also go inside a real prison cell, obtained from a now-defunct prison in Lorton, Va.

The museum floor also has a 911 Emergency Ops exhibit, where visitors can learn what it’s like to be a 911 emergency dispatcher by fielding incoming calls and deciding which emergency responders to deploy.

“Hopefully, people will come away with the sense that police are the public, and the public are the police,” Floyd said.

But the “heart and soul” of the museum, Floyd said, is its Hall of Remembrance, which is dedicated to fallen law enforcement professionals. Housed in a separate, solemn room, the walls of the hall displays photos of officers killed in the line of duty, as well as items life in memory of fallen offices at the memorial across the street.

“Unfortunately, over the last five years, 67 officers have been shot and killed in ambush-style attacks,” Floyd said. “It’s a very dangerous job.”

He added, “But the bottom line is, we owe a debt of remembrance of those men and women … to tell their story. Not just how they died, but how they lived.”

Floyd said the idea for the museum has been in the works since 1998. But it actually goes back further, he said, to when his former boss, New York Rep. Mario Biaggi, authored legislation for the law enforcement memorial across the street. It took seven years, but the memorial was dedicated in 1991.

Following the dedication, Floyd said organizers decided to “keep going” and push for a place to “educate people about the role of law enforcement in our society.”

Congress eventually voted to grant them use of federal land for the museum, but required them to build most of the museum underground, because of the historic nature of Judiciary Square. To that end, the 58,000-square-foot building spans three stories, including two that lie below street-level.

The museum, located at 444 E Street N.W., does not receive government funding. General admission tickets are $21.95 for adults, $16 for seniors ($14.50 for military, veterans, law enforcement and students with valid ID) and $12 for children under the age of 12 — but Floyd believes the space is well worth the price.

“I think this is going to be an absolute must-see destination for visitors coming to Washington D.C,” Floyd said.

FOLLOW US ON FACEBOOK FOR MORE FOX LIFESTYLE NEWS

For more, including ticketing information, visit the official site of the National Law Enforcement Museum.