Central Michigan University raised the Pro Concordia Labor flag, created in 1897, today. The international peace flag is yellow, purple, and white. No country uses that color combination.
It's also a part of CMU's history, said Dr. Hope May, Central Michigan University philosophy professor and international peace lawyer.
E.C. Warriner—the namesake of the university's administrative building—was a peace activist closely tied to the international movement.
The raising before Earth Day wasn't a coincidence, May said.
"Peace is not simply the absence of war," she said. "It is the harmonious alignment of diverse peoples, ideas, creatures. Of course, Earth Day, nature, is part of this project."
May hopes the event is a beginning for people's journey into the "Peace through Law" movement.
"I hope that people are enriched educationally, but I also hope that people meet other people who are drawn to these kinds of events and build those people-to-people bonds," she said.
The flag was raised at 1 p.m. on Friday, April 21.