Most people driving through Yellowstone would probably see Obsidian Cliff as another striking piece of volcanic scenery.

For thousands of years, however, people saw something much more valuable.

They saw stone.

Obsidian is volcanic glass, and when properly worked, it produces an extraordinarily sharp edge. Native people quarried the obsidian at this Yellowstone site for more than 11,000 years, shaping it into spear points, knives, scrapers, and other tools.

And the stone did not remain in Yellowstone.

Obsidian from the cliff traveled across an astonishing portion of North America. Archaeologists have identified it in artifacts found as far away as Texas, Washington, southern Alberta, and Ohio. At certain Hopewell sites in the Ohio Valley, about 90 percent of the recovered obsidian originated at Obsidian Cliff—roughly 1,500 miles away.

Today, scientists can use the trace elements in obsidian almost like a chemical fingerprint, allowing them to link an ancient artifact found hundreds of miles away to the Yellowstone source from which it came.

Obsidian Cliff wasn’t simply a geological formation. It was a quarry, a workshop, and a link in networks connecting people across North America long before Europeans arrived.

Long before Yellowstone became America’s first national park, Obsidian Cliff was already a destination.

Read the full story: Obsidian Cliff: Yellowstone’s Ancient Stone Highway

Carol M. Highsmith has spent decades photographing America—not only its famous landmarks, but also the ordinary places that future generations may otherwise never see.

Courthouses. Motels. Main streets. Churches. Farms. Neon signs. Roadside attractions. Small towns. Abandoned buildings. City skylines.

Her work matters because ordinary places do not stay ordinary forever.

Buildings are demolished. Businesses close. Roads change. Downtowns are redeveloped. Landscapes disappear. What seems commonplace today can become historically valuable tomorrow.

That idea sits at the heart of Highsmith’s work.

Her enormous photographic archive, now preserved at the Library of Congress, creates a visual record of America as it looked in our own time. In that sense, her work continues a documentary tradition that stretches back through photographers such as Frances Benjamin Johnston and the Farm Security Administration photographers of the 1930s and 1940s.

Highsmith’s photographs are often colorful, carefully composed, and beautiful, but they also serve as records.

Place matters.

Architecture matters.

Context matters.

The background details may someday be just as valuable as the main subject.

Perhaps the best way to understand Highsmith’s work is this:

Document the country now. Let the future decide what proves important.

I’ve written a longer article about Carol M. Highsmith, her career, and the extraordinary photographic record she has created: Carol M. Highsmith: Photographing America for the Future.

If you enjoy the images I share from her collection, that article explains the story behind the photographer—and why her work matters.

Carol M. Highsmith’s photograph Rural scene, South Dakota is striking because there is so little in it.

A lone tree stands in a broad sweep of golden prairie beneath a huge blue sky. A fence crosses the foreground, quietly reminding us that this is not untouched wilderness, but a working rural landscape shaped by people.

The tree is small.

The prairie is large.

The sky is larger still.

That scale defines the Great Plains. In a country like this, a single tree can become a landmark, and something as simple as a fence can tell us a great deal about how people have used and divided the land.

Highsmith made the photograph on September 16, 2009, but the scene feels almost timeless.

The full article takes a closer look at what this simple South Dakota landscape tells us about the prairie, rural America, and the quiet documentary power of an ordinary photograph.

A Lone Tree on the South Dakota Prairie