At one point, the largest airport in the world was going to be built right in the middle of South Florida. But the death of the Everglades Jetport is actually the story of the birth of the Big Cypress Nature Preserve.

The jetport came about from lofty ambitions in the late 1960s. State and local officials saw the population boom in South Florida and sought to create an airport between coasts. But this wasn’t any old airport: It would have six runways, accommodate the supersonic Concorde and be five times larger than New York City’s JFK airport was at the time. A new highway with a monorail service would connect the airport to the coasts. Early promotional materials boasted that it would just be 48 miles away from Marco Island.

The major problem: It would have been an ecological disaster. A 1969 environmental study from the federal government concluded that the jetport would “inexorably destroy the South Florida ecosystem and thus the Everglades National Park.”

A coalition of local hunters, Native tribes and environmentalists, including Marjory Stoneman Douglas, pressed authorities to find another location—and by 1970, with one runway already constructed, the project was abandoned. The coalition continued to lobby the federal government, and in 1974, Big Cypress was named the nation’s first national preserve.

The lone runway does get some limited use to this day as the Dade-Collier Training and Transition Airport.