ALONG WITH ALL the art on the walls, Boston seventh graders on a field trip to the Museum of Fine Arts last week saw some upsetting displays of modern-day racism.

It was another shameful chapter in Boston’s long-running history of making black people feel unwelcome. The incident received a lot of press coverage, probably because it illuminated something that can seem intangible at times but also all too prevalent.

Students from the Helen Y. Davis Leadership Academy, who are predominantly black and Latino, were subjected to racist comments by staff and visitors. Teachers at the charter middle school claim that museum security closely watched them while letting white students get away with touching the displays.

“The [worst] part about all of this is seeing the hurt look on my children’s faces as this was their first time experiencing racism first hand,” Marvelyne Lamy, an English teacher, wrote on Facebook. “It’s sad that although our students are well behaved and our teachers are well educated, that we are still seen as less than and as criminals.”

When she first complained to museum staff, Lamy didn’t get the apology she wanted, she said, but yesterday the MFA posted a public apology for the “range of challenging and unacceptable experiences” that made the students feel unwelcome.

Makeeba McCreary, the museum’s chief of learning and community engagement, said the incidents are under investigation and she plans to meet with school officials about it on Thursday.

Racism is a completely irrational mindset but also a powerful force that has caused wars and hardship going back centuries. Racism was one product of and also a contributing factor to the nation’s original sin of slavery, and it spurred the Civil War, which killed more Americans than any other conflict. That’s something worth remembering heading into Memorial Day.

It is also maddeningly difficult to get people to acknowledge that they did or said something racist, because as ever-present as racism has been in American life, it has also become more taboo in recent decades. While some racists have grown more vocal and violent in recent years, even avowed white nationalists prefer to be called “racialists” rather than racists.

The seventh-graders, whose trip to the museum was a reward for their good grades and behavior, were allegedly told by a museum staffer “no food, no drink, and no watermelon.” A student who danced in a musical exhibit was compared to stripper by a museum-goer, and a teacher heard one visitor complain about “[expletive] black kids in the way” of an exhibit of African arts.

There have been sincere efforts to grapple with racism locally. Boston Mayor Marty Walsh has convened a public dialogue on the topic. The Boston Globe thoroughly examined the region’s racial disparities and reputation for racism. Philanthropists led by tech entrepreneur Paul English are building a monument to Rev. Martin Luther King Jr. and Coretta Scott King, who advanced the cause of racial equality.

But if there is a way to ultimately defeat the ugly specter of racism it hasn’t been employed yet. The latest incident is a reminder that racism is not confined to musty history books, nor is it only a problem of the backwoods and sports stadiums. It continues to exist today even in the most prestigious corners of the city.