This giant pile of skulls tells a tragic story of American history

The bison is a majestic, if smelly, creature that has called North America home since prehistoric times.

But we nearly lost it to the dust of history.

In April 2016, the US House of Representatives and the Senate passed a bill that would honor the country's largest land mammal, the American bison, as our national mammal. The bipartisan legislation now awaits consideration by President Obama, who has the power to sign the bill into law - or veto it.

We recently published a defense on why this formidable beast deserves the recognition.

However, we just couldn't shake this one image of the bison that we found:

Centuries ago, US settlers massacred the species.

The bison used to roam the plains in numbers as high as 60 million, helping sustain indigenous people by providing food, clothing, shelter, and fuel. Many Native American tribes still consider the bison a sacred and spiritual symbol of their history.

Sadly, westward expansion during the 19th century nearly wiped bison from the Great Plains. Settlers slaughtered some 50 million for food and sport. Then they almost disappeared completely, according to the US National Park Service (our emphasis added):

In 1800, it was estimated there were forty million bison, by 1883, there were few wild bison in the United States - most were in Yellowstone National Park. By 1900, there were less than a thousand left in North America.

This slaughter also decimated Native Americans' most important resource. Their near-extinction all but ended the fight for native independence.

This dark story has at least one bright spot, though. Thanks to a concerted effort by ranchers, conservationists, tribes, and politicians, the bison has returned from the brink of extinction - and today these awesome beasts thrive.