The St. Louis Aquarium at Union Station opened a year and a half ago, but we didn’t get down there until recently. I’m glad we finally did.

At first, we weren’t sure exactly where it was in Union Station, so we parked at a meter on Market Street, looked around, and remarked on how deserted that section of downtown looked — particularly since this was at 11am on a Wednesday, right in the middle of a work day. Granted, a lot of the people who usually populate the nearby office buildings have been working from home for the last 15 months, but it was still a little eerie to have literally no one on the streets or sidewalks within two blocks of us.

The only exceptions were the rather bored-looking bellman and doorman at the Union Station hotel. Since all the other doors along Market Street were closed, we asked the bellman where the aquarium entrance was. He told us to keep going to 18th street, take a right, and we’d eventually get there. As we passed the giant downtown post office, we saw no signs of life there, either. I wondered how many of the small businesses that thrived on downtown workers in the before times had survived.

Once we went around the corner and up the block, it was an entirely different scene, with lots of families milling around or heading inside. After all, the school year’s over and everyone’s looking for a reason to get out of the house and go somewhere, anywhere. Fortunately, it wasn’t so crowded that we had to wait in a long line, and once inside, had easy access to the displays we wanted to see.

The aquarium is well laid out, with plenty of opportunities to learn about and touch sea creatures (horseshoe crabs, starfish, anemones). My wife was particularly taken by the arrow fish pool, where an aquarium docent explained that the fish shoot a stream of water at food hanging above, knocking it down to the surface, where they can retrieve and eat it. The docent held out a stick with some food a good 8-10 inches over the water and, sure enough, within two seconds, it was hit with streams from several of the fish, dislodging the edible feast in bits and pieces.

Martha’s other favorite was the river otter display, where a girl of about 9 or 10 stood in front of the window running her finger back and forth as one of the otters did laps — as if the animal was following her lead, not the other way around. When the otter headed up to the surface for a moment, I asked the girl, “Can you make it come back?” To which she immediately replied, “First it has to get some air!” Pretty smart.

Nearby, there’s also a digitized display with an animated otter ready to answer questions from attendees. The voice work is actually being done by a staffer backstage, but the synchronized animation is very well done, even if it reminded me of a “Black Mirror” episode entitled “The Waldo Moment.”

The best features of the aquarium are the multiple large viewing areas around its centerpiece 250,000-gallon tank full of sharks, devil rays, and several other species of fish. Merely moving from one window to another affords striking and mesmerizing new perspectives on the many animals swimming around inside. There are other galleries showcasing octopus, sea dragons, jellyfish, and more than 250 other species of sea life.

We spent about two hours perusing the aquarium. If we’d been there with a young kid, she’d no doubt have wanted to climb the overhead ropes course, run through the mirror maze, and ride the giant ferris wheel. But we were happy to just walk back to our car and go grab some great barbecue at Pappy’s.