Harrelson has attended environmental events such as the PICNIC'07 festival that was held in Amsterdam in September 2007. PICNIC describes its annual festival as "three intensive days we mix creativity, science, technology, media, and business to explore new solutions in the spirit of co-creation". He once scaled the Golden Gate Bridge with members of North Coast Earth First! group to unfurl a banner that read, "Hurwitz, aren't ancient redwoods more precious than gold?" in protest of Maxxam Inc. CEO Charles Hurwitz, who once stated, "He who has the gold, makes the rules."