John Denver was just 53 years old when he died in a plane crash on Oct. 12, 1997.

The country and pop superstar and 1975 CMA Entertainer of the Year was flying an experimental two-seat plane near Monterey Bay in California when he plunged into the water from approximately 500 feet. He was the only occupant of the aircraft at the time. Denver left behind three children.

The "Rocky Mountain High" hitmaker was an experienced pilot, but his plane ran out of fuel in one tank, and he was unable to safely switch to the other tank before plummeting to his death.

While Denver had repeatedly faced alcohol-related legal issues in the years leading up to his death, a toxicology report revealed no drugs or alcohol in his system.

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Denver had earned 14 gold and eight platinum albums in the United States over the course of his career, and his music was also popular worldwide. An early stint as a folk singer in the Chad Mitchell Trio led to Denver's first hit, when Peter, Paul and Mary cut his song, "Leaving on a Jet Plane" and turned it into a No. 1 hit in 1969.

Denver's solo career caught on with the release of "Take Me Home, Country Roads" in 1971, which reached No. 2 on Billboard's all-genre Hot 100 chart. He went on to score a long string of hits across genres in the '70s, including "Rocky Mountain High," "Sunshine on My Shoulders," "Annie's Song," "Back Home Again," "Thank God I'm a Country Boy," "I'm Sorry" and more.

He earned a number of American Music Awards, Emmys and Grammys, as well as an ACM Award for 1974's Album of the Year. "Back Home Again" also won Denver a CMA Award for Song of the Year in 1975.

Denver was also a passionate advocate for a number of political and social causes, including environmental sustainability and world hunger, and much of his music reflected those beliefs in his lyrics. He was inducted into the Songwriters Hall of Fame in 1996, one year before his death. Denver received a posthumous star on the Hollywood Walk of Fame in 2014.

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