At the Art Institute, 'Paradise Lost' is a sprawling artwork defying description. You just have to see it.

For a smart guy, I can be pretty thick.

Let me explain.

For decades, I've been admiring Gustave Caillebotte's “Paris Street; Rainy Day” at the Art Institute. It's hard not to.

A huge painting of pedestrians hurrying along Haussmann Boulevard, it's got the realism I like, softened by the stirrings of Impressionism, circa 1877. You can stand far away and absorb the whole scene, or swoop in to notice the woman's delicate black veil.

Yet never, in all the years I gazed at it, did I ever pause to think, "Heyyyy ... this guy's pretty good. I wonder what ELSE he's painted?" Not once.

That lapse was made painfully clear seeing the Caillebotte show — a sprawling, comprehensive exhibit, shifting Caillebotte from one-trick-pony to significant, complete artist, introducing a world that you — OK, me — never imaged.

I won't review the whole show — my colleague Kyle MacMillan did that marvelously. Just go.

Be sure to study the placards. Otherwise, you'll miss what's going on. Look at the picture above, "Interior, Woman Reading."

What's striking is the woman is the dominant figure, in the foreground, studying a newspaper, then a typically masculine activity. While the man is sprawled on the sofa, holding a novel, considered at the time a feminine vice. Caillebotte is playing with us, toying with our expectations.

The more things change ...

The Caillebotte exhibit, “Painting His World,” is reason aplenty to visit the Art Institute. But there's an additional surprise that hasn't gotten the publicity it deserves.

I'm tempted to leave it at that. Stop reading now, go as a blank slate and then return after you've encountered it ...

You're back? Already?

On your way to the Caillebotte show, you usually pass through the Asian gallery. And there, along 100 feet of the south wall, is Raqib Shaw's “Paradise Lost.” You stopped in your tracks and gaped. Don't feel bad. Everybody does.

How to describe it for those who cheated and kept reading? The life's journey of the Calcutta-born, Kashmir-raised, London-based artist. Conveyed in a wild allegorical explosion that defies description. The museum tries: "An epic and tumultuous journey that represents the very nature and breadth of human existence ..."

Raging seas, collapsing palaces, a horse wrestling a zebra, leopards, bears, placid baboons in a cherry tree — well, placid except the one strangling a fawn. Bejeweled, painted in automobile enamel using syringes and porcupine quills.

Dozens of visitors crowd around, stepping back, drawing in close. I'm deliberately not publishing photos.

"You have to see it," said Madhuvanti Ghose, associate curator of arts of Asia at the Art Institute. "Because no amount of photography actually captures the kind of details that your eye picks up."

I wondered how the Art Institute found Shaw, which is like asking how Chicago dug up that Picasso fellow when commissioning a sculpture for Daley Plaza.

"He has such renown," began Ghose. "When he first made it in the West, he was a shooting star. Everyone heard about him. It's rare for a young artist from India to make it with his first show and be so provocative. He has a lot of American patrons who absolutely adore his work. He was definitely on our director's radar, my radar. Anyone who was into art knew about Raqib Shaw. We have trustees who are big fans of his."

Shaw has been painting "Paradise Lost" since 2009 and plans to continue for the rest of his life — another 30 feet or so.

I said the painting struck me as both contemporary yet classically Hindu — the crowned beast king howling at the moon is wearing Doc Martens — and for a second I thought I'd slid into the ditch, sensitivity-wise.

"Actually, you are one of the few people who is even able to visually see any Indian influences," she said. "Most people see the Western references, because so much of Raqib's work has been a nod to the European masters. He really has taken not just painting but medieval renaissance painting as his source of inspiration."

I was about to apologize when she continued.

"... but you are totally right in that his technique, his visual vocabulary, that was shaped by his experiences growing up in Indian and Kashmir. The ambiance of Kashmir ... You see it in the detailing. You see it in the adornment. Also a tension in the work. The different chapters in the work are like a symphony."

Or an epic poem. I've seen it once, plan to go back, and already hate the fact Chicago has to let this masterpiece go in January. The Art Institute should just keep it, send Shaw a blank check and tell him: Sorry, but it's ours now. Please forward new sections as they're finished.

Alas, the art world doesn't work that way.