Answer: The Shedd Aquarium

Built in the early 20th century, the Shedd Aquarium—located in Chicago, Illinois—was a marvel of engineering, architecture, and an all-around ambitious project. Funded by the fortune of wealthy Marshall Field & Company’s president John Graves Shedd, the aquarium (still in operation today and worth a visit if you’re ever in the area) features stately marble and iron buildings, beautiful architecture, and a rich collection of sea plants, animals, and creatures from around the world.

In fact, the Shedd Aquarium was the first inland aquarium to feature a permanent saltwater display and, in our opinion, the story of how they filled their massive displays is as interesting as the general history of the aquarium itself. In 1930, a train of twenty insulated railroad tank cars traveled the U.S. railways all the way from Chicago straight down to Key West, Florida on a continuous loop to collect ocean water right from the source and bring it to the aquarium. At the end of the rail-driven feat, the very-northern Shedd Aquarium was filled with no less than a million gallons of tropical ocean water.