THE SOLE SURVIVING speaker from the March on Washington is vividly recounting that historic day as if it were yesterday. Rep. John Lewis tells me he remembers the faces of his fellow civil-rights figures, and the sea of hundreds of thousands lining the Reflecting Pool. And keenly, the Georgia Democrat this month recalls Martin Luther King Sr. providing advice shortly before his son was due to step to history’s dais. “Make it plain, son,” Lewis recounts the senior King reminding in his quick pep talk. “Make it plain. And make it real.”

Today, on the 50th anniversary on that monumental day, Google makes it plain with a home-page Doodle to commemorate Dr. King’s iconic “I Have a Dream” speech. And as it rings with the reverend’s own moving words, the elegant illustration makes it real.

“I have a dream today.” “All men are created equal.” “A table of brotherhood.” And “the content of their character.” The autumnal-toned artwork features a virtual scrim of those ingrained-in-history passages from the last five build-to-crescendo minutes of the resonant speech that still inspires. “Google” is set in the background, its “L” formed by the Washington Monument. And there in the foreground, Dr. King stands with his back to us, overlooking a sea of silhouettes both brown and white — his right arm raised precisely as it was when the reverend reached his sweeping “Let freedom ring!” rhetorical climax.

(The full text of the copyrighted speech can be found at the National Archives.)

That day, and that speech, would of course help change a nation — providing a come-together battlecry for unity and brotherhood, freedom and justice. From arrests to deaths, the roiling struggle would continue, but two years later, not far from the site of that speech, President Johnson would at last sign legislation to provide equal voting rights.

THEN AND NOW: Demonstrators at the March on Washington on Aug. 28, 1963 (left); and people line the Reflecting Pool to mark the 50th anniversary of the March on Aug. 24, 2013. (AP)

Today, the March on Washington — what Dr. King called “the greatest demonstration for freedom in the history of our nation” — will be marked with anniversary ceremonies on the Mall. President Obama is scheduled to speak from those same Lincoln Memorial steps at 3:05 p.m. — “minutes after the ringing of a historic bell from the 16th Street Baptist Church in Birmingham, Ala., will mark the time when King came to the microphone in 1963,” according to The Post. (At that church, in that year, four girls were killed in a bombing while readying for a “youth day.”)

Also scheduled to be on hand today will be former presidents Bill Clinton and Jimmy Carter, as well as viral 9-year-old “Kid President” Robby Novak.

Fifty years ago, the March’s throngs included such entertainment celebrities as Sidney Poitier, Lena Horne, Charlton Heston, Paul Newman and Joanne Woodward. Today, the show-business figures scheduled to speak will include Oprah Winfrey and Forest Whitaker from the current hit film “The Butler” (based on Post reporter Wil Haygood’s 2008 article), which depicts the sweep of the civil-rights struggle.

The folk group Peter, Paul and Mary performed at the 1963 March; today, the surviving Peter Yarrow and Paul Stookey will perform.

Journalist Soledad O’Brien and actor Hill Harper will emcee the ceremonies, set to begin about 11 a.m.

And Rep. Lewis himself — the March’s youngest featured speaker 50 years ago, at age 23, and now its surviving elder statesman — is scheduled to appear.

“I’m lucky and very blessed to still be here,” Lewis tells me, “and to see the changes and progress made as a nation.”

RELATED: To read all The Post’s March on Washington coverage, just click HERE.