WASHINGTON, DC.- On Tuesday, the much-delayed International African American Museum in Charleston, South Carolina, announced a new opening date for the institution — June 27 — and officials have their fingers crossed that this date will stick.

The museum was due to open in January on the weekend after Martin Luther King Jr.’s birthday, but those plans were scrapped in December when officials recognized problems with the center’s humidity and temperature controls. Those issues have been resolved, according to Tonya M. Matthews, the museum’s president and CEO.

“We have had a year’s worth of doors opening and closing doors,” Matthews said in an interview, explaining how the museum tested its climate controls to ensure that its permanent collection of 300 artworks and historical artifacts would be protected from Charleston’s notoriously high heat and humidity.

The $120 million project, which has been underway for more than 20 years, is devoted to telling the story of the middle passage, the journey that began in Africa with the capture of millions of Africans who were forced to cross the Atlantic to Gadsden’s Wharf in Charleston and other ports. The museum is on the site of that former wharf, overlooking Charleston Harbor, where many enslaved Africans first entered the United States. Remnants of the wooden wharf were found by archaeologists in 2014 during an exploratory dig for the museum site.

During the postponement, the museum also commissioned two new works by a local artist, Fletcher Williams III, who specializes in multimedia installations. One large sculpture will be on view in the gallery leading visitors to “Seeking,” a short video by filmmaker Julie Dash that reinterprets the coming-of-age traditions of the Gullah Geechee, the descendants of West Africans brought to the southeastern coast, into a narrative of resilience. Other objects in the museum’s collection include work by Malian photographer Seydou Keïta and pottery by enslaved artist David Drake.

“As this magnificent new museum demonstrates, Charleston isn’t just a city where history happened — it’s a city where history is still being made every day,” Charleston Mayor John Tecklenburg said in a statement. “I couldn’t be prouder of this extraordinary achievement.”

Supporters of the project have waited more than two decades to see the center open. Delays have plagued the museum throughout its construction, which involved setbacks because of the COVID-19 pandemic and employee turnover. The institution also found itself in the middle of a political fight concerning the state budget in 2017.

Having overcome those hurdles, the museum’s leaders will have the opening take place nearly a week after Juneteenth, the annual commemoration of slavery ending in the United States after the Civil War. The celebration marks June 19, 1865, when 250,000 enslaved people in Galveston, Texas, received news from a Union general that put into effect the Emancipation Proclamation, issued nearly 2 1/2 years earlier.

A team of designers led by architect Henry N. Cobb, Walter Hood and Ralph Appelbaum have created 100,000 square feet of space that includes nine galleries, a genealogy center and a memorial garden.

Matthews said history weighed on the museum, and employees were being trained on cultural competency and empathy to accommodate viewers reacting to the history of enslavement depicted at the center.

“There is a lot of emotion associated with this museum,” she explained. “Some folks have waited so long, and they thought this moment would never come. You don’t know whether to laugh or cry or shout or sing. You probably will want to get that all in.”

This article originally appeared in The New York Times.