WILLISTON — Celebrate Earth Day with a full day of hands-on activities Saturday, April 18, 9 a.m.-5 p.m., at the Missouri-Yellowstone Confluence Interpretive Center near Williston. The free come-and-go event welcomes families, homeschool groups and anyone interested in exploring the natural environment. Children must be accompanied by an adult.

Activity stations throughout the day encourage exploration of the prairie landscape and local ecosystems. Examine owl pellets to uncover bones, fur and other remains, learning about local wildlife and the food chain. Use the sun and natural materials to create cyanotype prints. Explore the components of healthy prairie soil and make animal track casts. Investigate specimens from the region at interactive nature tables.

Trails around the confluence offer opportunities for an eco-scavenger hunt searching for signs of spring and prairie wildlife. A nature journaling station encourages observation, sketching and connection with the surrounding landscape.

Guided nature hikes depart at 10 a.m., noon, and 2 p.m., exploring nearby trails while highlighting local plants, wildlife and ecosystems.

This event is part of the ND250 commemoration celebrating America’s 250th anniversary.

Fort Buford State Historic Site and the Missouri-Yellowstone Confluence Interpretive Center are managed by the State Historical Society of North Dakota.