Poet and novelist John Green, an outspoken environmentalist, has died.

John Green is best known for his critically acclaimed novel Green Eggs and Ham, which is set in rural North Carolina and is also a movie.

He wrote his own play and is the founder of the environmental organization Greenpeace.

He has also been known for writing poems that have inspired a wide range of artists.

Green Eggs & Ham has won four Hugo Awards, including a 2016 Tony Award for Best Original Screenplay.

It has also won five Academy Awards and six Golden Globes.

Green is also an author of several books and is an outspoken critic of the use of fossil fuels in transportation.

He also was a regular on the Oprah Winfrey Show and wrote a biography about him.

He died Sunday at age 73.