It's been more than 21 years since Jim Brady scrambled his way up a river bank in eastern Honduras into one of the greatest finds of his career.

The discovery was a little — well, we'll call it weird — from the start. But the work that Brady performed back in 1994 changed our very understanding of how man lived thousands of years ago. It was, in many ways, an anthropological, archaeological game-changer.

The fact that Brady, a specialist in cave archaeology and a professor at California State University, Los Angeles, initially had no idea what lay ahead of him simply adds to an already intriguing story.

A story of grave robbers. Ancient civilizations. Hidden treasures. Glowing skulls.

Somebody call Harrison Ford already.

"I was picked up at the airport," says Brady, recalling his first trip to see the discovery, "and I'm being taken out to the site, and we stop and I get out. It's the middle of the night. I walk back to the truck, and there on the door, I see this thing called 'Cave of the Glowing Skulls.' I had never even heard this before. I always referred to it as de Cueva del Rio Talgua.

"Without realizing it, I had gotten onto a moving bus."

The cave on the Talgua River had been known for a few years, but earlier in 1994, explorers had uncovered a previously undiscovered upper chamber containing ancient bones. It was a burial spot, an ossuary, and Honduran officials called in Brady — then at George Washington University in Washington, D.C. — to take a look before the inevitable grave robbers and vandals did their damage.

A film production company had agreed to supply some badly needed funding for the expedition. And that's where things turned weird.

A movie that involves archaeologists at something called Cueva del Rio Talgua simply wasn't catchy enough. So the marketing minds got together and came up with "glowing skulls."

It wasn't really scientific. In fact, it immediately irked the professionals involved.

But, the thing is, it wasn't far off. The bones did kind of glow. They had been submerged under water at one point in time — centuries ago — and were covered with calcium carbonate.

"So there were these white, sparkly bones," Brady says. "And it preserved them perfectly."

The publicity people milked it. Others marveled at ancient marble vessels in the cave. But Brady, moments after climbing a handmade ladder into that upper chamber, saw much more than that.

"I remember going down there knowing I had a week to do this study, and I didn't even think that it would take that long," Brady says now. "But we get into the chamber and all the sudden I realize, it's not the marble vessels. I realize what's important here is all the skeletal material. We have hundreds and hundreds of people. So I just kind of went into this zone."

Brady took samples and detailed the site. It was an archaeologist's dream, providing clues and raising more questions about the history in this part of Central America.

"We did it, and as I'm flying out ... I'm sitting in the plane, drinking my complimentary Scotch, sipping it and relaxing, and all of the sudden it hit me," Brady says. "'My God, what an incredible experience that was.'"

Rethinking a civilization

Weeks later, Brady saw the results of radiocarbon dating — another costly bit of science paid for by the dreaded "glowing skulls" publicity — and was even more stunned. Brady was guessing that Cueva del Rio Talgua dated from around 400 B.C. to 700 A.D.

The radiocarbon dating pointed to anywhere from 1400 B.C. to 800 B.C. Much, much earlier than anyone had expected.

Brady had missed it by a few hundred years.

"By a lot of hundred years," Brady laughs now. "I was so shocked I couldn't think. Like, I was just confused. I didn't realize for a moment the implications of it, because it was so unexpected."

The discovery meant a few things. For one, it cemented — thanks to earlier work in the area and in other parts of Honduras — the idea that caves used as ossuaries was a definite pattern. It helped identify the people there as probably non-Mayan. And it helped show a level of society that was previously unknown.

"It changed our notion of the complexity of Honduran society at this very early time, because someone was making these marble vessels, which were made from this single block of marble and had to be chipped out and then hand-smoothed. And the ones that we had in the cave were really, really thin-walled. So this was an extraordinary piece of workmanship," Brady says. "In general, marble vessels are probably the artifact most associated with elite status. So it would indicate that at this very early time — much earlier than people were thinking — we already had a fairly developed social system with social inequality. With leaders."

A cave of the past

All the hoopla that surrounded the "glowing" skulls, Brady acknowledges now, did help bring some attention — not to mention the much-needed funds — to his efforts. But in the end, that wasn't even the story. Even though that story persists.

"For years, I resisted calling it, 'The Cave of the Glowing Skulls.' But that’s how it became known. So it's like, 'OK. Whatever,'" he says. "It's receded far enough in the rearview mirror that it's taken the sting out of it."

The cave, badly looted since, is a lightly-visited tourist spot now, though what's left of the ossuary is off-limits to the public. Brady still does fieldwork virtually every year, but he's finished with Honduras. He works sites in Guatemala and Belize instead.

His adventure, 21 years ago, had its challenges. But Cueva del Rio Talgua and its glowing skulls always will be a big part of Brady's life and a major find in that part of the world.

"Yes, it was worth it," he says without hesitation. "It was an amazing discovery."