Originally, "Candle in the Wind" was meant to celebrate another star. It its 1973 release, introduced by the words "Goodbye, Norma Jean," Elton John and his lyricist Bernie Taupin paid tribute to Marilyn Monroe - describing not so much the film star as the turbulent life of a sensitive person destroyed by her stardom.
Taupin later revealed that he hadn't thought up the metaphor of a candle in the wind himself but had been inspired by an obituary to another female star who died tragically young: Janis Joplin, who overdosed on heroin in 1970 at the age of 27.
Then, on August 31, 1997 came the horrifying news: Lady Di had died in a car collision.
Elton John was in shock.
After meeting Diana in 1981 when he sang at a birthday celebration for Prince Andrew, they'd become close friends. Only six weeks before her death, she'd consoled him at the funeral of another friend, the fashion designer Gianni Versace.
From Marilyn to Diana
The royal family contacted Elton John to ask whether he would sing at Diana's funeral. The song "Candle in the Wind" immediately came to mind, but the text about a Hollywood star would have been inappropriate at a memorial service in Westminster Abbey.
John contacted Bernie Taupin in California, who wrote a new text, drawing parallels between the life of Diana and that of Marilyn Monroe, who had also died at age 36.
"I wanted to make it sound like a country singing it," said Taupin. The text was finished within hours. "From the first couple of lines I wrote, the rest sort of fell into place."
At Diana's funeral on September 6, 1997 - seven days after the tragedy - Elton John sat at the piano and sang "Goodbye, England's Rose." Later, he described the experience as "surreal." "What was going through my mind was 'Don't sing a wrong note. Be stoic. Don't break down and just do it the best you can possibly do it without showing any emotion whatsoever.' My heart was beating quite a lot, I have to say."
The effect was overwhelming, "like someone firing an arrow" through his emotional defenses, Prince Harry later revealed.
Only 12 years old, he and his brother William had to endure the eyes of the world on them at the memorial service for their mother - and both were determined not to cry. But hardly another eye of the 2,000 in attendance at Westminster Abbey was dry at the words "Now you belong to heaven / And the stars spell out your name."
Read more: Why I didn't watch Princess Diana's funeral
A phenomenal charts success
A production in West London's Townhouse Studios was finished posthaste with piano and vocals by Elton John, balanced by a string quartet and an oboist to accommodate the special arrangement by Sir George Martin. On September 13, 1997, exactly a week after Diana's funeral, "Goodbye, England's Rose" was released on the B-side of a record with another Elton John song, "Something About the Way You Look Tonight."
The sales outperformed everything to date, totaling 658,000 on the first day alone. One week later, they stood at 1.5 million units, and after 15 days, three million. Sales in the US eventually totaled 11 million, and in Germany 4.75 million copies.
It's estimated that at the flush of sales, "Goodbye, England's Rose" changed hands six times per second.
With 33 million units sold worldwide, it is sometimes called the best-selling single ever, although that rank is disputed. At an estimated - but unverifiable - 50 million units, Bing Crosby's "White Christmas" still holds the top spot in the Guinness Book of Records. Many of those records had been sold before the introduction of the pop charts in the 1950s.
Elton John performed "Goodbye, England's Rose" only once - at Diana's funeral - and never again.
In concerts he always performs the earlier, 1973 version of "Candle in the Wind." The artist specified that sales proceeds from the 1997 version go to charitable causes that had been close to Diana's heart.
A fund was set up, and after it was closed 15 years later in 2012, a total of 138 million British pounds ($177 million) had been tallied up, of which an astonishing 38 million pounds ($49 million) came from the sale of "Candle in the Wind" alone.
Here's the song text:
Goodbye England's rose
May you ever grow in our hearts
You were the grace that placed itself
Where lives were torn apart
You called out to our country
And you whispered to those in pain
Now you belong to heaven
And the stars spell out your name
And it seems to me you lived your life
Like a candle in the wind
Never fading with the sunset
When the rain set in
And your footsteps will always fall here
Along England's greenest hills
Your candle's burned out long before
Your legend ever will
Loveliness we've lost
These empty days without your smile
This torch we'll always carry
For our nation's golden child
And even though we try
The truth brings us to tears
All our words cannot express
The joy you brought us through the years
Goodbye England's rose
From a country lost without your soul
Who'll miss the wings of your compassion
More than you'll ever know.