Union Station in St. Louis was built in 1894 as the largest and busiest railroad terminal in the world. For decades it moved passengers across the country. Then rail travel declined, the station sat underused, and by the late twentieth century it had been repurposed into a shopping mall that never quite found its footing. The latest iteration — a hotel, entertainment district, and aquarium — works better than any version I've seen in my years here.
The aquarium itself opened in 2019 inside the original terminal building. It's compact by major-city aquarium standards but well-designed, with a focus on freshwater and river ecosystems that makes sense for a city sitting at the confluence of the Missouri and Mississippi. There are sharks — a few varieties in the main tank — and stingrays you can touch, and a floor-level tunnel where fish swim overhead. The exhibits move from ocean to river and back, loose in their geography but engaging throughout.
The terminal's grand hall still has its vaulted ceiling and stained glass, now lit for the aquarium context. It's a strange combination: the architecture of nineteenth-century rail travel housing tanks full of marine life. But Union Station has always been about moving people through, and the aquarium continues that in its own way.
The surrounding complex includes an indoor Ferris wheel, mini golf, and a few dining options. Bring kids and budget more time than you think you need. The main tank alone warrants a long stop.