Moon jellies are mesmerizing.

I’m always glad to spend some time peering into a tank where the moon jellies drift, but also somehow contract their entire selves to glide along in deep quiet.

We’d come to the Georgia Aquarium, which keeps company in downtown Atlanta with the World of Coca-Cola, the National Center for Civil and Human Rights, and a large parking deck on about 20 acres of a plaza known on maps as Pemberton Place. To its south is Baker St. and Centennial Olympic Park; to the north, Ivan Allen Jr. Blvd. and a massive substation behind walls. For just an instant I thought that was Irwin Allen Jr. Blvd., and was disappointed to realize otherwise.

At 11 million gallons – which is apparently how major public aquariums are measured – the Georgia Aquarium is listed on Wiki as the sixth largest in the world and the largest in the United States, and I believe it. The structure is hub-and-spoke, with an enormous, vaulting hall with sizable exhibit spaces radiating from that hall: Tropical Diver, Ocean Voyager, Explorers Cove, Cold Water Quest, Southern Company River Scout, Dolphin Coast, Truist Pier 225 and Aquanaut Adventure.

Five days before Christmas, much of the human population of Atlanta was there, gawking at the sea and land creatures. We did our own gawking.

The invertebrate collection included much more than moon jellies. There were other kinds of jellyfish, too, looking like the sort of thing that if you see on the beach in Australia (or anywhere), you’d better not to touch.

They puff along.

Other invertebrates. Such as the inspiration for Patrick Star.

And of course, fish. Many, many fish.

Including the inspiration for Nemo.

Small creatures can be intriguing or even enchanting, but what really packs ’em in are the likes of whale sharks, the largest fish species know to science, and one of the aquarium’s signature attractions. There’s no shortage of other kinds of sharks as well, it always being Shark Week at the facility: tiger sharks, silvertip sharks, blacktip reef sharks, and great hammerhead sharks.

More from the sea: Manta rays, goliath groupers, green sea turtles, Japanese spider crabs and weedy sea dragons. Freshwater creatures include, but are hardly limited to, Asian small-clawed otters; black spot piranhas — just how many kinds of piranhas are there, anyway? — snapping turtles; banded archerfish; discus fish; and shovelnose sturgeon.

A few birds are on hand, such as spoonbills and ibises. Ones that subsist on fish, in other words.

In case we hadn’t had enough gators in Florida, the aquarium had a few Georgia gators, including a rare albino. I take it Georgia gators were the inspiration for Albert in Pogo.

We saw the dolphin show. My still camera wasn’t the best for capturing the action, and there was a lot of jumping and splashing, but squint and the second shot looks like an impressionist work featuring a line of mid-air dolphins.

A separate show features seals and sea lions, doing seal and sea lion things for fish rewards.

About half as many people crowded into the aquarium would have made for a better experience, but I can’t begrudge the Georgia Aquarium its massive popularity, since it delivers the aquatic goods. Better a crowd than too few people. They’re out seeing real things. Often better, I believe, to see some part of the physical world than an electronic simulacrum.