Greta Thunberg in Rapid City

Greta Thunberg and Tokatawin Iron Eyes address the crowd that marched from Memorial Park to Rapid City Hall on Monday, Oct. 7, 2019.

RAPID CITY, S.D. — A teenage environmental activist from Sweden who made headlines at the recent United Nations Climate Action Summit participated in a rally Monday in Rapid City with hundreds of others.

Greta Thunberg, 16, spoke out against the Keystone XL Pipeline that is expected to pass through western South Dakota and urged activists and politicians to listen to indigenous people when it comes to climate change.

She spoke alongside Tokata Iron Eyes, a 16-year-old from Pine Ridge who planned the rally and invited Thunberg to speak at the Pine Ridge and Standing Rock reservations.

Between 300 and 400 people attended the rally in Rapid City that started at Memorial Park and ended at City Hall, according to police spokesman Brendyn Medina.