In the late Cretaceous period, about 80 million years ago, vast stretches of the North American continent were under water, between what is now the central Rocky Mountains and the eastern Appalachians, and extending south from the Canadian provinces to the Gulf of Mexico (as we know it today). We've all read about, and maybe even had in our hands, seashells and other fossils originally deposited on the shores and floor of that ancient inland sea. Fossilized remains of the great dinosaurs are uncovered regularly in the Dakotas and Wyoming, and the broad agricultural richness of the soil of the Great Plains attests to the seabed that once covered the farmlands of the mid-continent.
Over the intervening ages, the geology of the continent and the dynamics of the Earth's oceans and weather eventually caused the sea covering much of North America to recede, to withdraw and leave the central lands high and dry, with only subtle reminders of its once-impressive span.
But what if...just if...in our lifetime, the sea returned, erasing the Gulf Coast, and flooding its way up the heartland, covering much of Texas, portions of New Mexico, all of Arkansas, Missouri, Oklahoma, Kansas, Colorado, Nebraska, parts of Wyoming, and most of the Dakotas? What if, in 100 years, Denver was known for its seaside attractions and Lincoln, Nebraska was one of the world's major commercial shipping ports?
In "The Great Nebraska Sea", science fiction Allan Danzig, writing in Galaxy Magazine in 1963, spins a wild tale of just such an event. He paints a short-story picture of a massive earth-shaking event taking place over only a few weeks and months in 1973 as a hitherto discounted series of fault lines running north to south along the eastern edge of the Rockies, ripped open, dropping the central states by 1,000 feet, and creating a spillway big enough for the Gulf of Mexico to rush in. In just a few short months, the United States as Americans knew it in 1973 is totally transformed - at the cost of more than 14 million lives, and the watery loss of eight US states. Over the next 100 years, the nation recovers, resets itself, and takes on a new and incredibly (unexpectedly) prosperous persona, building on the new trade and tourist opportunities afforded by the Great Nebraska Sea.