I was an eyewitness to history.

Only this time, my eyes were filled with tears.

I had never before cried so much in my life. And not since.

And I didn’t even know her.

How do you calculate grief so palpable it makes you choke?

All stories are unique. I’ve covered quite a few in my 50 years in journalism.

OPINION

But this was different — a time when sorrow was as invasive as a tear-duct virus — bidding goodbye to a woman the country called their English rose.

On this, the 20th anniversary of Princess Diana’s death, allow me to take you back to early September 1997, shortly after the 36-year-old ex-wife of Prince Charles — the future king of England — was killed in a car crash speeding through a tunnel in Paris with her lover.

The city of London was in mourning and the world was beginning to catch up.

In what turned out to be an inspired move, I checked into the Kensington Palace Hotel — which happened to be next to an aerie of grief: Princess Diana’s home at Kensington Palace, where her funeral cortege would begin its trip to Westminster Abbey nearly a week later.

Luckily, I had taken a coterie of Brit’s top royal journalists (James Whitaker, Richard Kay, photographer Edward Edwards) to dinner during Princess Diana’s much ballyhooed visit to Chicago in June 1996, to help raise money for the Northwestern University hospital’s cancer center.

So I phoned up a little payback from the premier royal watchers, who tend to pop up like mushrooms after rain wherever Princess Diana went, to check out the lay of the land.

I didn’t have to go far.

The world of sorrow generated by Princess Diana’s cruel death had chosen to camp out in front of the palace, giving me a bird’s eye view from my window.

It was extraordinary.

The Brits’ stiff upper lips were moving; men were uncontrollably weeping; traffic was a mess.

Hundreds of thousands of mourners were now trekking to Kensington, Buckingham and St. James’ Palaces; marching and kneeling and sobbing; bearing wreaths of flowers in cellophane wrappers; clothes pinning poems to the Hickory and Hawthorne trees in Kensington Park; leaving behind cards, balloons and sweet, childish toys at the palace gates.

And at night, a sea of twinkling candles ignited by mourners lit up Kensington Gardens, where the silence of sadness included the smell of candle wax, the scent of fragrant tuberoses and the click click click of baby carriages.

Princess Diana’s army was carrying floral banners to the Kensington Palace gates, installing a royal carpet where they believed the popular princess of the people really lived: outside the palace walls.

Here is a sampling of what I penned in 1997 under the heading of “Postcards from London.”

• “The city is in mourning. During Di’s funeral, the national lottery will not be drawn, shops will close and the Orient Express will not head to Venice.”

• “The paparazzi are being pilloried for ironically killing their ‘golden goose.’ It’s ironic the elegant princess, who loved high fashion, was wearing a black jacket and white pants when she was killed.”

• “And the ‘cad’ appeared. Major James Hewitt, who kissed and told and broke Di’s heart, issued a statement as he choked back tears: ‘I loved her and miss her terribly.’ ”

• Richard Kay says she called him six hours before her death.

“Said Kay: ‘She was as happy as I have ever heard her . . . . She told me she had decided to radically change her life. She was going to complete her obligations to her charities . . . and then, around November, would completely withdraw from her formal life. She would then, she said, be able to live as she always wanted to live.

“Not as an icon . . . but as a private person.”

• “Prince Charles wept as he walked across the moors around Balmoral Castle, reportedly staying up late the night before drinking gin martinis and calling friends into the wee hours of the morning.”

• “Charles’ inamorata, Camilla Parker Bowles, has been out of sight. It is expected she will maintain a low profile.”

• “Prince Charles not only had reportedly sent Diana a recent note beginning ‘My Dearest Diana,’ and ending ‘lots of love,’ but Di’s close reporter pal, Richard Kay, claims Charles and his lover, Camilla Parker Bowles, hadn’t been together for more than a month. Oh, well.”

• “Supermodel Cindy Crawford says she got a call from Diana 24 hours before her death, telling her: ‘For the first time in my life, I can say that I’m truly happy.”

• “A Palestinian has offered $1 million for the wreck of the crushed Mercedes, Diana’s death car. He says he wants to turn it into a memorial for the princess.”

In the end, it wasn’t over.

Princess Diana is dead.

But her death made us feel what we suspected all the time: that this shy, but sly, English girl with the backward glance was only trying to give the world a hand.

Water, no rain!

Load ’em up!

Head ’em out!

Watch for Specialty Print Communications, a Texas corporation with its entire platform in Illinois, to dispatch 45,000 bottles of water via truck at their Niles facility Friday to Hurricane Harvey-pelted Houston. “Thought we should give back,” said SPC president Adam LeFebvre.