Last night's installment of Ken Burns's 5-night epic National Parks: America's Best Idea explained how the feathered-hat craze of 1900 actually helped one of the world's biggest natural wonders, Florida's Everglades, on its way to becoming a National Park.

As the clip explains, turn of the century women were so obsessed with feathered hats — particularly those with the kind of feathers an Egret only grows when nurturing her young — that a whopping 95% of Florida's shore birds were killed by poachers greedy for the feathers that were worth more than their weight in gold:

"The Audubon Society tried unsuccessfully to persuade women not to buy hats with feathers, while the powerful millinery industry used its influence in Congress to defeat a series of national laws aimed at stopping the slaughter of birds."

Finally, a conservative Congressman named John F. Lacey got a bill passed that made transporting birds killed in violation of any state law a federal crime, and the contentious years that followed it (which included a war between poachers and game wardens) set the stage for the Everglades' preservation.

Without getting into any blatantly obvious lessons about the ethics of fashion (surely that's the name of a class somewhere), those are some pretty stupid looking hats! Great-Grandma: WTF?

The Call For A Featherless Hat [PBS]
The National Parks: America's Best Idea [PBS]