Thursday’s solemn National Day of Mourning observance in downtown Plymouth, Massachusetts, will recall the disease and oppression they say 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.’”