Racism continues to show its face in the United States, as visitors of the National Museum of African American History and Culture found a noose in an exhibition about segregation on Wednesday afternoon.

Park police removed the noose, and the gallery was reopened after an investigation. The investigation will be ongoing, but police have said the area is safe.

Insider Access | National Museum of African American History and Culture

“The noose has long represented a deplorable act of cowardice and depravity—a symbol of extreme violence for African Americans. Today’s incident is a painful reminder of the challenges that African Americans continue to face,” said Lonnie Bunch, the director of the museum, in an e-mail to staff.

The National Museum of African American History and Culture – known as the NMAAHC, or as the Smithsonian, since it’s a Smithsonian Institution Museum – opened on September 24, 2016 in a ceremony led by then President Barack Obama. As the only national museum “devoted exclusively to the documentation of African American life, history and culture,” it has collected more than 36,000 artifacts.

Wednesday’s incident is the latest in a string of racist acts of vandalism around the country. As Smithsonian Magazine points out: less than a week earlier, a noose was found hanging from a tree outside of the Hirshhorn Museum, another Smithsonian establishment. And on Wednesday morning, reports surfaced that a vandal sprayed the word “nigger” on LeBron James’ Los Angeles home.