Members of Native American tribes from around New England gathered Thursday in the seaside town where the Pilgrims settled – not to give thanks, but to mourn Indigenous people worldwide who’ve suffered centuries of racism and mistreatment.

The solemn National Day of Mourning observance in downtown Plymouth, Massachusetts, recalled the disease and oppression that European settlers brought to North America.

“We Native people have no reason to celebrate the arrival of the Pilgrims,” said Kisha James, a member of the Aquinnah Wampanoag and Oglala Lakota tribes and the granddaughter of Wamsutta Frank James, the event’s founder.

“We want to educate people so that they understand the stories we all learned in school about the first Thanksgiving are nothing but lies. Wampanoag and other Indigenous people have certainly not lived happily ever after since the arrival of the Pilgrims,” James said.

“To us, Thanksgiving is a day of mourning, because we remember the millions of our ancestors who were murdered by uninvited European colonists such as the Pilgrims. Today, we and many Indigenous people around the country say, ‘No Thanks, No Giving.’”

It’s the 52nd year that the United American Indians of New England have organized the event on Thanksgiving Day. The tradition began in 1970.

Indigenous people and their supporters gathered on Cole’s Hill, a windswept mound overlooking Plymouth Rock, a memorial to the colonists’ arrival. They also livestreamed the event.

Participants condemned what organizers describe as “the unjust system based on racism, settler colonialism, sexism, homophobia and the profit-driven destruction of the Earth” and planned to march through downtown Plymouth’s historical district.

This year, they also planned to highlight the troubled legacy of federal boarding schools that sought to assimilate Indigenous youth into white society in the U.S. as well as in Canada, where hundreds of bodies have been discovered on the grounds of former residential schools for Indigenous children.

Brian Moskwetah Weeden, chairman of the Mashpee Wampanoag Tribal Council, said on Boston Public Radio earlier this week that Americans owe his tribe a debt of gratitude for helping the Pilgrims survive their first brutal winter.

“People need to understand that you need to be thankful each and every day – that was how our ancestors thought and navigated this world,” Weeden said. “Because we were thankful, we were willing to share … and we had good intentions and a good heart.”

That wasn’t reciprocated over the long term, Weeden added.

“That’s why, 400 years later, we’re still sitting here fighting for what little bit of land that we still have, and trying to hold the commonwealth and the federal government accountable,” he said.

“Because 400 years later, we don’t really have much to show for, or to be thankful for. So I think it’s important for everyone to be thankful for our ancestors who helped the Pilgrims survive, and kind of played an intricate role in the birth of this nation.”