Photo via UWGB
Many of us having been celebrating Earth Day for as long as we remember--but it hasn't always been this way. As evidenced by this photo from a march on the first Earth Day in 1970, it's taken the dedication, cunning, and the unflinching love of the environment of some very passionate people to bring about the awareness we have today. Now, we all know that we've got a long ways to go, but Earth Day is about celebrating the progress we've made--and a big part of that should be honoring the environmental heroes who've helped get us this far. This is by no means a comprehensive list, but here are some of the great men and women who've defined modern environmentalism--these green heroes deserve a huge Earth Day salute.