Meet ‘Mr. Earth Day,’ the Man Who Helped Organize the Annual Observance

Nearly 50 years after 20 million Americans participated in the first Earth Day on April 22, 1970, more than 190 countries mark the annual day for raising awareness of environmental causes. And the stakes only grow as the years go by.

Though Earth Day has been dogged by rumors that it was founded by a murderer and as communist propaganda, the truth is much more straightforward — but no less fascinating. TIME spoke to Denis Hayes, a real organizer of the first Earth Day, dubbed "Mr.

Nearly 50 years after 20 million Americans participated in the first Earth Day on April 22, 1970, more than 190 countries mark the annual day for raising awareness of environmental causes. And the stakes only grow as the years go by. Though Earth Day has been dogged by rumors that it was founded by a murderer and as communist propaganda, the truth is much more straightforward — but no less fascinating. TIME spoke to Denis Hayes, a real organizer of the first Earth Day, dubbed "Mr.