There are more mysteries out there in Nebraska than you might expect. In those vast expanses of prairies, grasslands, sandhills, and rocks lie some of the region's most fascinating fossils. The world's largest mammoth fossil was unearthed here years ago, and the Ashfall Fossil Bed site is an active excavation that you can watch unfold before your eyes. However, Ashfall isn't the only active site Nebraska has to offer.

Hudson-Meng Bison Bonebed is located in far northwestern Nebraska in the Oglala National Grassland. It contains the ancient skeletons of approximately 600 bison. They aren't the same species of bison that exist today; these animals lived tens of thousands of years ago on the American plains.

The site was discovered by Albert Meng, the rancher who owned the land, in 1954. When digging a pond to water his cattle, he came across a few bones. And then some more bones. And when the bones just kept coming, he knew he'd stumbled on something extraordinary.

Meng showed his find to neighboring rancher Bill Hudson, who agreed that the site looked important. They contacted Chadron State College, but it would take more than a decade for excavation to begin.

In the 1970s, Dr. Larry Agenbroad led the first round of excavation. He and his team found hundreds of bison skeletons from 10,000 years ago - the largest bison kill site of its kind ever discovered. But what had happened to this huge group of massive mammals? At the time, the prevailing theory was that the bison had been driven off of a nearby cliff by Alberta Culture hunters and moved to the current site for butchering. Arrowheads and other tools were found at the site which, in part, drove the theory that the animals were butchered at the site.

In the 1990s, another excavation took place and the theory behind the site's origin began to evolve. Scientists now thought that the bison had died of natural causes, perhaps when trying to escape a grassland fire. There appeared to be no signs of human butchering, which led researchers to believe that some other force had claimed the animals' lives.

In the early 2000s, yet another theory emerged. The ancient tools discovered on the site were found to be from several different cultures, suggesting that the site was a hunting ground used over a very long period. Could the bison have died at different times, but in the same paleontological period?

That's a debate that continues to this day, and the mystery may never be definitively solved. Today the site remains an active excavation. You can visit to see the dig evolve and expand over time. Even the pictures here aren't representative of exactly what the site looks like today because it is always changing.

The site is now managed by the US Forest Service in Chadron. The main dig site is protected by a large barn. Visitors can view the actual dig site, but there's plenty more to experience here, both in the barn and in the visitors center. Interpretive displays and informative markers are everywhere. Learn about the animals, the cultures of the time, and the history of the area.

Rangers often lead tours and activities, such as this demonstration of an 'atlatl' spear being thrown. You can also choose to simply wander the site on your own, taking in all of the fascinating information about Nebraska's ancient history.

Because the site is located on the Oglala National Grassland, its surroundings are absolutely gorgeous. You can imagine what the Native Americans who once inhabited this land must have seen as they stalked their prey tens of thousands of years ago. You may even find fossils, arrowheads, or other interesting objects on the grounds. But don't try to take them as souvenirs - it's illegal to remove any materials from the site.

This is a must-see destination for anyone who loves natural history, paleontology, archaeology, and the raw beauty of northwestern Nebraska. If you're extra adventurous, hike the three-mile Bison Trail to the breathtaking Toadstool Geologic Park.

This video gives a great idea of what it's like to visit this unique attraction.

The Hudson-Meng Bison Bonebed site is open from Memorial Day through October 1st each year. There is a small admission fee, or you can buy a season pass and visit the site all you want in the summer! Find contact information here.

You can read more about the history and future of the research at the site right here.