From left Cierra Brockman, Montana Chevalier and Cassidy Olson of Manitowoc Lincoln High School stand with arms locked during a school walkout Wednesday, Mar. 14, 2018, at Manitowoc Lincoln High School in Manitowoc, Wis. The walkout was part of a national effort to honor those who died in the shootings at Marjorie Stoneman Douglas High School in Parkland, Florida, a month ago.