Forgoing the option of expanding in the cramped quarters of the Museum Campus as well as out into Lake Michigan, the Shedd Aquarium instead took to the skies, tethering and propping up on stilts rivers encased in glass.

From anywhere in the city, you can look up and find eels slithering their way through interlocking tubular loop-de-loops. You can also watch schools of tuna rhyming with the murmurations of starlings, something that never fails to mesmerize.

Popular among lovers are the bioluminescent critters. At night they twinkle and glow above where stars have long ago been blotted out by urban light pollution. Surely, under this shimmering airborne ocean, a very romantic evening can be had.

The most popular attraction, of course, are the humpback whales soundtracking the city with their plaintive songs. This is but the latest leg on their Darwinian odyssey: from sea to land then back to sea again, and finally, to the skies. If the entire structure collapses, well, it's back to land again in a sort of Douglas Adams dysfantasia.

Near where the loops dip to within a few feet off the ground—usually in the park—children play next to Charybdis, the Kraken and the Leviathan.

((Im)possible Chicagos is a series of hallucinatory joyrides through one hundred and twenty-five asynchronous Chicagos.)