In a small dark room painted forest green tucked into the third floor of the Seattle Art Museum, you’ll find Lorenzo Ghiberti’s 500-year-old Gates of Paradise. The Gates are not really gates; they’re three gleaming golden panels, spotlit like diamonds on dark velvet, held inside clear oxygen-free cases filled with nitrogen.

The heist-movie lighting is more fun—and, literally, more illuminating—than the way the panels appeared when I caught them two months ago at the Metropolitan Museum of Art. There, they were subsumed in another tableau, installed in the reconstructed patio of an early 16th-century Spanish governor’s castle, slightly overcome by the natural light streaming in.

Truth be told, there is no bad way to see Ghiberti’s gilt-bronzed reliefs. They are spectacular objects. To make them, Ghiberti revived the Roman lost-wax casting technique. He created 10 panels to be installed in the door of the Baptistery of the Duomo in Florence—and all together, they stood 20 feet tall and weighed a mighty three tons. It was a project that took Ghiberti and his crew 27 years to complete, from 1425 to 1452. Legend has it that Michelangelo dubbed them “the Gates of Paradise,” and Michelangelo’s famous Adam-and-God-touching-hands moment at the Sistine Chapel echoes Ghiberti’s depiction (see bottom left below).

The panels—3 of the 10 are at SAM, each 31.5 square inches—synthesize tradition and innovation. In keeping with medieval style, Ghiberti portrayed several scenes in a single panel: the creation of Eve from Adam’s rib (see front and center above), Adam and Eve with the serpent (back left), the expulsion (front right).

He dispensed with other traditions. He blended emerging perspectival rules of painting and the in-the-round depth of sculpture. He scrapped the limited frame of the Gothic quatrefoil seen on other sides of the Baptistery. These panels are open squares, waiting for action.

They get action. Seemingly every millimeter of depth is used to create the range of relief. Figures and objects in the farthest distance are given the least detail. And relief is related to time: At the top right of the Adam and Eve panel above, check out the angel at the middle right, coasting through the archway and into the real space of the viewer. She becomes dimensional as she moves.

Some of the objects in the highest relief have broken off over time, but for the most part, the panels are in mint condition.

In a single panel, Ghiberti makes room for an army of soldiers, and an entire cityscape. Here’s his teeming, urban vision of the David and Goliath story:

If you’re wondering why that one is more worn, it’s because it hung lower. It suffered from the affections of admirers.

The third and final panel is the tale of Jacob and Esau, using the trope of the raked floor and graduated arches to achieve perspective.

(As an aside, this summer I visited Borromini’s perspective gallery in Rome, where an attendant walks the distance to puncture the illusion. Here it is:

The distance looks 37 meters long, but is only 8 meters long. The sculpture at the far end looks life-size, but is only 60 centimeters high.)

This exhibition, The Gates of Paradise: Lorenzo Ghiberti’s Renaissance Masterpiece, is at SAM through April 6. It stopped in Atlanta, Chicago, and New York before this, and marks the first time the panels have traveled outside Italy to be displayed. SAM is the last stop before they return to Florence to be mounted permanently at the Museo dell’Opera del Duomo. It’s said they’ll never tour again.

The current tour is a way to show off the restoration of the panels, which were ravaged by the elements in all their years outdoors, culminating in a 1966 flood of the city that tore six of the panels right off the doors. Today, when you visit the Baptistery, you see replicas. The originals have been undergoing restoration for more than 25 years.

There’s much explanation in the exhibition about the cutting-edge laser technique that has cleaned the reliefs while preserving the gilding—so that you’re seeing what Ghiberti and company actually did (look for gilding brushstrokes), not a restorer’s in-fill—but the real drama takes place in the art, not the restoration. I’ve seen this show twice already. I’ll be back at least that many times.