Experts often come from the places you'd least expect. Even so, when Discovery Channel producers were searching for an authority on the trans-Saharan gold trade, they probably weren't expecting to find Richard Smith.

"I'm as waspy-looking a person as you can find," said Smith, who has been a professor at Ferrum College for 32 years. "I just got very interested in West Africa in grad school."

In September, he was contacted by Discovery Channel producers who were working on a new 13-episode series with Josh Bernstein, an explorer best known for his History Channel archaeological series "Digging for the Truth."

The Discovery Channel series, scheduled to air in the summer, will attempt to answer questions about history through recent archaeological discoveries. For one episode, "In Search of Africa's El Dorado," the producers wanted Smith to help them answer the question: What happened to the West African gold trade?

"During what we would call the late Middle Ages, West Africa was the major producer of gold in the Eurasian part of the world," said Smith.

The gold, he said, was mined near Mali and shipped to commercial cities on the southern edge of the Sahara.

"This gold would come from the south along the Niger River to places like Timbuktu," said Smith. "It would be shipped by camel caravan across the desert to a number of different places."

The foremost, he said, was Morocco. From there, it was traded into Europe and the Middle East. But in the 16th century, something happened, and Discovery Channel came to Smith to find out what.

"In the 16th century, a Moroccan sultan came along -- Ahmad al-Mansur. He's really very badly pressed for money because he has these big dreams and he's going to make Morocco a modern country," said Smith.

At the same time, Ahmad al-Mansur, which means "the victorious one," was constructing a palace to honor his own legacy. As funds ran low, the sultan decided to send an army across the Sahara to conquer the gold mines.

"He didn't really have an idea where it was mined," said Smith. "He thought the army could find the mines themselves and this would satisfy all of his financial problems."

An army of about 4,000 soldiers armed with muskets and cannons set out from Morocco. Only half made it across the Sahara, said Smith.

"I've been across the Saharan desert, which is like 2,000 miles with the occasional oasis," he said, adding that Saharan oases are nothing like Hollywood oases. "They're pretty nasty places."

The army attacked the Songhai Empire, including Timbuktu. With its powdered weapons, the army killed everyone in its path and looted everything.

"But they never find the gold mines," said Smith. "The Songhai Empire never controlled the mines."

For "In Search of Africa's El Dorado," Bernstein begins his search in Ghana and travels through the Songhai Empire until he gets to Timbuktu.

"He [Bernstein] says, 'What happened to this gold?' and in Timbuktu, somebody says, 'Oh, it went across the desert with al-Mansur's army,'" said Smith.

When Bernstein and the Discovery Channel crew arrive in Marrakech, Morocco, they "find" Smith, who picks up the gold trail and leads the crew to al-Mansur's palace, telling the story as they go along.

"Most of it [the gold] was melted down and made into coin," said Smith. "Al-Mansur spent almost as much money building and maintaining this army as he did plundering his enemies, and so just about all of the wealth was consumed by his own government and paid out in the form of wages."

The palace, however, was completed, with more than 300 rooms and covered with marble and gold. But a later sultan, Moulay Ismail, envied al-Mansur's fame as "the golden one." Ismail had the palace dismantled. Today, only the stone ruins remain.

"The only permanent inhabitants that are left is the nesting cranes," said Smith. "It's a really haunting, eerie place."

The gold trade, said Smith, didn't disappear from there. Instead, the gold took a different route. Rather than sending the gold north via camel caravan, it went south to the coast where it was loaded onto Portuguese, Dutch and English ships bound for Eurasia.

The 13-episode Discovery Channel series, the name of which is "top secret" and wasn't revealed to Smith, will air from July through September. Other episodes will include archaeological discoveries in Peru, Turkey and Israel.

"In Search of Africa's El Dorado" will air in August or September and the waspy-looking West African expert will share with the world his love of history and the morality tale of the trans-Saharan gold trade.

"It really sort of typifies what happens to the wealth from plunder, wealth from loot," said Smith. "It never lasts. It flows through the plunderer's hands and it's gone."