A display of historic wanted posters is a reminder that you do not want to end up on a wanted poster. (Jenna Kendle/Express/Jenna Kendle/Express)

On Saturday, the National Law Enforcement Museum finally opens its doors to the public — 18 years after Congress authorized its construction in D.C. The timing feels fortuitous: Police/community relations in the U.S. are less than ideal, and the museum will be a setting for thought-provoking education and conversation that could help bridge the gap. “It’s intended to be a place to learn, a place for dialogue, a place to ask the tough questions people want to know,” says executive director David Brant, a former director of the Naval Criminal Investigative Service. “The overriding mission is to strengthen the relationships and bond between law enforcement and the communities they serve.” Here are six things to know ahead of the grand opening.

It’s an airy, mostly underground facility.

Visitors enter the Judiciary Square museum at street level through a glass pavilion, then descend one level to the ticketing booths. At this point, the striking U.S. Park Police Eagle One Bell helicopter — which was used to rescue survivors of the 1982 Air Florida crash in the Potomac River — comes into view. Visitors then cross the mezzanine, which offers a panoramic glimpse of the museum, and go down once more to reach the exhibit floor. “It’s a beautiful facility,” Brant says. “The atmosphere is unique in that it’s open, airy and inviting, and everything is right in front of you: The exhibits are all viewable from every other part of the museum.”

High-profile artifacts include a revolver used by an officer to injure outlaw John Dillinger and a poster circulated after the Lindbergh baby kidnapping. (Jenna Kendle/Express/Jenna Kendle (Express))

You can take a turn as a 911 emergency dispatcher.

One of the museum’s standout interactive exhibits puts visitors in a pretend 911 dispatch center, where they’ll receive a pre-recorded call for help via a simulator. “They’ll literally play the role of dispatcher,” Brant says. After dispatching the proper authorities — one patrol car? Two? An ambulance? — visitors continue playing out the situation. If it’s a noise complaint about neighbors, the “dispatcher” might ask the caller if he or she saw any underage people, drugs, alcohol or weapons. “These are real-life scenarios, and the visitor will get a feel for what goes on day to day and the protocols involved,” Brant says. “How many of us really know what a 911 operator does?”

There’s an intense officer training simulator.

One of the primary goals of the museum is to let visitors “walk in the shoes of law enforcement,” Brant says. Up to 25 people at a time can participate in a training simulator (for an additional $5 charge); two volunteers are selected to use simulated weapons, while the others portray witnesses to a crime depicted in interactive video segments. “Most law enforcement agencies across the country use these simulators to train their officers on how to react to certain situations,” Brant says. Participants can take whatever action they think is appropriate to calm a given predicament, such as a frantic victim. “These are difficult, not-real-clear situations that around a million law enforcement professionals face every hour, every day, around the country,” Brant says. “It’s all intended to educate and leave the visitor with a sense that, quite frankly, things aren’t as simple sometimes as they seem, or as black and white in terms of decision-making.”

A few law enforcement vehicles are included among the museum’s displays, but the keys aren’t inside so don’t even think about it. (Jenna Kendle/Express/Jenna Kendle (Express))

They outdid themselves with the artifacts.

A motorcycle used by an undercover agent as he infiltrated the Sons of Silence gang. A bullet-riddled Arkansas Game and Fish Commission truck involved in a 2010 shootout. Those and about 1,000 more of the museum’s 20,000 artifacts will be on display at any given time, Brant says, and many will be housed in one of eight “history capsules” that illustrate how policing has evolved — from English jurisprudence to the American West to the civil rights era. “We have [former FBI Director J. Edgar] Hoover’s desk; we have Eliot Ness’ credentials,” Brant says, referring to the Prohibition agent who helped bring down Al Capone. There’s also a capsule spotlighting items from the Sept. 11 terrorist attacks: fragments from one of the planes that hit the World Trade Center towers, an NYPD patrol car door, a Port Authority safety helmet and a firearm that was found melted inside a safe in one of the towers.

There’s a peaceful place to honor the fallen.

The museum is an extension of the adjacent National Law Enforcement Officers Memorial — two curving, 304-foot-long walls that honor those who died in the line of duty. The first name was inscribed on the wall in 1994, and there are now more than 21,000 etched into the blue-gray marble. The museum’s Hall of Remembrance has “a beautiful seating area and reflective wall that will highlight, with pictures, those who lost their lives in 2017,” Brant says. “And then next year, we’ll honor those who lost their lives in 2018.” Visitors can learn about each officer whose name is inscribed on the memorial via an interactive kiosk; there’s also a display of objects that friends and relatives have left in tribute to the officers’ sacrifices and service.

It’s striving to be a platform for constructive dialogue.

An exhibit called “Five Communities” provides a detailed look at innovative programs developed to improve police/community relations in Cleveland; Dallas; Chicago; Somerville, Mass.; and Charleston, S.C. Brant notes that the museum will host 30 or so programs for kids, educators and adults each year, including an upcoming talk on the opioid crisis. “The ability to establish dialogue about how to move forward positively is going to be the compelling part of this whole initiative,” he says. “You can come in and get a new perspective or additional perspective than what you brought in. Not pro, not con, just hopefully new information.”

National Law Enforcement Museum, 444 E St. NW; daily beginning Sat., 10 a.m.-6 p.m. (open until 9 p.m. on Thursdays), $14.95-$21.95 (free for kids 5 and under).