On Dec. 28, 1973, President Richard Nixon signed the Endangered Species Act. The powerful law charged the federal government with saving every endangered plant and animal in America.
Sparked by the 1970s environmental movement, the Clean Water Act transformed America’s polluted rivers. The Delaware, once an industrial cesspool, is one of the success stories, but its urban stretches remain a work in progress.
Fifty years on, Denis Hayes is still trying to keep the spirit that made Earth Day a world-changing event alive — and to refocus its energy on climate change.
