Animals with backbones (vertebrates) make up only 4% of the species on our planet. Yet when you walk into a natural history museum, they’re all you see. The dinosaur skeletons stretching across a ballroom? Vertebrates. Dioramas starring posed buffalo, lions, or zebra? Vertebrates. The endless cases of delicate stuffed birds? You guessed it: vertebrates.

“It’s a real tragedy: far and away, most of the animal kingdom is tiny,” said Jack Ashby, Manager of the Grant Museum of Zoology at University College London. “Natural history museums really only ever put big animals on display. That’s not very representative of nature.”

A new permanent exhibit at the museum, called the Micrarium, tries to fill the gap by displaying the smallest organisms. Microscope slides containing cross-sections of insects and other invertebrates are stacked wall-to-wall in a small room, lit from behind. Visitors can see the detail of the eye-level slides—but the point is larger than any of the individual animals.

“All these specimens around you and above you make the point visually that this is what the diversity of life is,” he said. “What I wasn’t prepared for is how beautiful it would look.”

Modern natural history museums are cathedrals that exude awe. Visitors wander through and expect to be amazed at every turn—by seeing animals distant in time or space (even if non-living), gazing upon sparkling gems and minerals, or having a physical experience of the vastness of the universe at human scale. In that context, how can tiny microbes and invertebrates compete? “These bacteria can live in hot water and make energy from sulfur!” isn’t quite as compelling—and certainly not as visually appealing—as a stuffed ape or 100-foot whale model.

To give credit where credit is due, museums definitely try to show more than just the back-boned animals among us. But it’s an incredible challenge. Soft-bodied animals rarely leave fossils behind worthy of display. Many invertebrates shrink up and become unrecognizable if they’re not preserved in liquid, but keeping a specimen intact while putting it in public view is difficult. The Smithsonian (full disclosure: my full-time employer), for example, has a giant squid on display in the Sant Ocean Hall. But it’s kept in an air-tight tank holding some 1,500 gallons of preservative fluid, which is not a sustainable solution for smaller, more cash-strapped museums.

And then there’s the issue of size. How do you put bacteria or other microbes, invisible to the human eye, on display in a museum? Some curators will build blown-up models of single-celled organisms to at least give them a place in the exhibition hall. But when you choose to blow up a handful of microbes, you do it at the expense of portraying their biodiversity.

What’s remarkable about the Micrarium is that vast diversity is its centerpiece. It channels that same awe that visitors see when they gaze upon a T-rex skeleton, but focuses its point on the grandeur of life's biodiversity. The point isn’t to learn the details of insect evolution or invertebrate zoology. The focus is to just be amazed at how many kind of animals are out there—ones that you’d never see, not because they live far away or are extinct, but because they too small to be easily seen.

“The wow we’re getting [at the Micrarium] is from the volume and the prettiness of the display,” said Ashby. “One specimen on its own wouldn’t get the same response.”

I haven’t ever seen a microscope slide on display in a museum. But almost all museums have them in the storerooms. Slides were once the only way to sort and study small animals, but modern-day microscopy and other technologies have made them obsolete. So they collect dust—until an innovative curator comes along and brings them to light.

“The stereotype of dusty old bones in a storeroom is not true,” said Ashby. “We’re doing new things with old things.”