Robert Zemeckis’ “The Walk” will be a big hit. The director who made “Back to the Future” and “Forrest Gump” knows how to make movies. But people won’t go to the film, which opened this weekend, to see a circus trick. They’ll go for one reason only: to see the real World Trade Center, the only way you can now.

Politicians who are confused about why the electorate is so angry should go, too — to see what the last 14 years looks like to normal people.

“The Walk” has a serviceable enough made-for-TV plot. It’s a “boy makes good” story: Young Philippe Petit dreams of being a tightrope walker. Through talent and persistence, he succeeds, picking up a pretty girl and a band of plucky brothers along the way. He makes global headlines when he walks the void between the towers of Notre Dame in Paris, 30 stories up.

But there’s no blockbuster here, save for the real prize: New York’s Twin Towers. The World Trade Center, circa 1974, is not a prop in this 3-D film, but the star.

In a Paris dentist’s office, Philippe sees a magazine photo feature of the towers under construction — and stops cold. New York is doing what only New York could do: build something at a scale he can’t even comprehend. He has to go to Gotham — and make the buildings his own by walking between them, 1,300 feet up.

His epiphany is extreme.

But it’s a reminder that, for 28 years, the Twin Towers defined New York. After the World Trade Center attacks, newspapers ran stories about how immigrants came here based on nothing but a postcard they had seen — a photo with that distinctive Manhattan skyline.

Left unspoken in the movie is that the World Trade Center defined New York for the terrorists, too. They, too, eventually made the buildings their own — by destroying them.

The most poignant parts of “The Walk” are the towers.

When Philippe gets to Manhattan, he walks onto the construction site and puts his hands on the arches at the base of the buildings. The camera shoots up, close up, to the top, replicating the view so many New Yorkers and visitors once experienced. How could something be so tall?

In shot after shot, we see the old lobbies, the old elevators, the old plaza with the Fritz Koenig “Sphere” sculpture in the middle, the old view of Manhattan out the windows.

And just like Philippe, we see all this close enough to touch it.

When I was watching it, I thought of “Titanic,” James Cameron’s film from nearly two decades ago — another digital recreation of a lost world.

Except that this was our world — and it was our choice to keep it lost.

Al Qaeda set out to mutilate our skyline. They succeeded. New York could have rebuilt new, modern Twin Towers after 9/11. And we could have done it quickly.

But we did not. We spent more than a decade and $4 billion building a tower that could fit on any generic skyline.

To be clear: The city can live with this decision. We are, indeed, living with it.

But we should not pretend that it is not a psychic wound. People care, not just in the city, but around the country and the world.

It’s no coincidence that way back in 2005, none other than Donald Trump seized on architect Ken Gardner’s elegant plan for new Twin Towers. It was typical Trump: a press conference in Trump Tower, a lot of bombast and slamming of impotent politicians, and then . . . nothing, except publicity around a new “Apprentice” season.

Most people today likely don’t remember that stunt — but it was early evidence that Trump was tapping into something more serious pols didn’t see.

At the end of “The Walk,” Philippe notes that after his coup, Port Authority officials gave him a pass to the World Trade Center’s observation deck. The expiration date was crossed out. In its place was the word “forever.” The towers slowly fade to black. By this point, the audience is sniveling.

We don’t need to be told that forever didn’t last very long, and that the towers have now been gone for half the time that they were there.

People aren’t crying for the Twin Towers, though.

We are crying for the past 14 years. We could have done better. And — obviously — not just locally.

Pols should be grateful that the public is angry. When anger turns to acceptance, that’s when we should worry.

Nicole Gelinas is a contributing editor to the Manhattan Institute’s City Journal.