Denis Hayes served as the international chair of Earth Day 1990, where he expanded the event to a global scale, mobilizing 200 million people across 141 countries. This effort significantly boosted recycling initiatives worldwide and set the stage for the 1992 United Nations Earth Summit. Hayes initially gained recognition as the national coordinator of the first Earth Day in 1970, which brought 20 million Americans into the streets to demand environmental reforms.

After 1990, he continued his environmental leadership as president of the Bullitt Foundation, focusing on sustainability and social equity in the Pacific Northwest, and oversaw projects like the creation of the Bullitt Center, one of the world’s greenest buildings.

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