WHEN YOU SEE those billboards on I-95 for the Franklin Institute's big Genghis Khan history exhibit, opening May 9, you can only imagine the army of highbrow cultural experts that it took to amass and transport and meticulously display that grand collection of 200 artifacts linked to the

13th-century conqueror.

And then there's the actual guy who made the show happen: Don "Dino Don" Lessem.

Lessem is a Delco-based pre-history buff who works from a small, cluttered desk in a big old farm house with goat droppings on the front porch, the life-size head of a brachiosaurus from "Jurassic Park" in the shed and - at least for the moment - sundry pieces of metalwork, armor and ceramics from the time of Genghis and Kublai Khan (Genghis' grandson) sitting on a dining room side table.

"There's a lot of Genghis Khan stuff here," he says when the Daily News calls to arrange a visit. "You can try on a helmet!"

Besides being the creative force behind "Genghis Khan: Bring the Legend to Life," Lessem is also, in no particular order: a credited adviser to the movie "Jurassic Park," the bankroller of an archaeological dig that unearthed two of the world's largest dinosaurs, a former "Jeopardy!" contestant, a man wanted briefly in Mongolia for the alleged theft of a mummy - and a longtime contributor to Highlights magazine.

Over the course of 10 years as Highlights' Dino Don, he sent 11,000 personal replies to children who mailed in questions about dinosaurs. One kid wondered if Lessem used his mustache to brush dirt off their bones.

So what's a live-wire like him doing in a business like this, building globally sourced museum exhibits for heavy hitters like the Franklin Institute?

Traveling blockbusters like the Genghis Khan show help keep the lights on at museums these days, and Lessem is one of several colorful, independent producers who create them and shop them around. "The 'Mummies' guy is a boxing promoter," he notes. (That would be Marcus Corwin, the South Florida impresario behind "Mummies of the World.")

Lessem and Corwin are super flyweights compared to John Norman, the former Fleetwood Mac tour promoter behind the King Tut, Titanic and Pompeii blockbusters. But Lessem's well-received Genghis Khan exhibit has drawn 800,000 visitors in its eight stops before Philly, including 200,000 at Chicago's Field Museum.

The Franklin Institute anticipates an audience of about 150,000 based on preshow research, says museum senior vice president Troy Collins.

The name Genghis Khan tested well with local museum-goers. "He's got some brand equity," Collins says.

And the museum has a solid track record with Lessem, whose "Giant Mysterious Dinosaurs" exhibit connected well with Philly families in 2012. In the museum business, Lessem has a rep for building shows that are both fun and legitimately educational, Collins says.

Granted, he adds: "Maybe you and I wouldn't decorate like that. I tried to put a Tyrannosaurus on my front lawn - my wife wouldn't let me."

To build world-class science museum shows with Delco-farmhouse-class credentials, Lessem pulls in experts to fill in the gaps. "Lotta gaps," he says. "It's all gaps."

Contractors build the exhibit cabinetry. Techies in California handle the electronics. Crews that work the museum circuit do the setups and breakdowns. "They're like roadies," Lessem says.

For the Genghis Khan show, Mongolian, Chinese and American artists painted backdrops, built a battle-size catapult and re-created the Court of Kublai Khan. Lessem enlisted two curators from the Smithsonian Institution and another from Columbia University to nail the historical accuracy of it all. When the exhibit comes to Philly, a Broadway designer will be in charge of the lighting.

Lessem is the idea guy and the coordinator of it all - including contracts and transportation - and he writes the words for the exhibit displays, words being his area of bona-fide expertise.

He was getting by as a freelance science writer when a series of happy accidents led him to specialize in dinosaur stories (he's published 45 children's books on the topic and several for grown-ups, along with contributing to TV shows like "Nova") and then to branch out into museum shows, starting with dino exhibits.

In one lucky break, he ran into a grad student at a Society of Vertebrate Paleontology meeting who had a snapshot of a gigantic leg bone. "I said, 'Buddy, that's bigger than T. Rex. Where's the rest of him?' " Lessem recalls.

The young scientist had found the bone in Patagonia (South America) but lacked the $6,000 to finance a dig to unearth the rest of the skeleton. "I said, 'I can find $6,000,' " Lessem remembers. "That's how I got into the dinosaur business."

His full-size casts of that 123-foot-long Argentinosaurus and a Patagonian Giganotosaurus are now on permanent exhibit in Atlanta.

In a luckier break still, he says, "Somewhere along the line, I met [Michael] Crichton."

The Jurassic Park author connected him to Steven Spielberg to advise on the movie. After filming wrapped, Lessem enlisted Spielberg's assistant to get the studio's OK to use the movie's props in an exhibit. "He went to Universal Studios and said, 'Steven said . . . ,' and I got all this stuff."

The exhibit toured the country, earning $3 million for dinosaur research. Lessem's company, ExhibitsRex, has since built 11 additional traveling dinosaur exhibits. About 8 million people worldwide have seen them.

Now, it's one thing to build a razzle-dazzle exhibit around movie props and cast copies of dinosaur skeletons. It's a much higher order of business to borrow Mongol antiquities from the far reaches of Eurasia for a landmark cultural exhibit, says William Fitzhugh, one of the Smithsonian experts whom Lessem hired for the Genghis Khan show.

On this side of the globe, the museum brass who book history shows expect a level of academic gravitas - preferably at the doctorate level. Lessem has a bachelor's degree in art history from Brandeis and a master's in animal behavior from lunchpail UMass Boston.

"He's an original," says Harvard-credentialed Fitzhugh. "I was thinking, 'How in the hell is he going to pull this together?' "

The idea for the Genghis Khan show popped into Lessem's head during an expedition to Mongolia, where, he says, "the only thing you hear more about than dinosaurs is Genghis Khan." He paid calls to museums and cultural ministers in Mongolia, China and Russia, lining up artifacts from all three countries for the exhibit's 2009 debut, in Houston.

On second thought, make that two countries. "The Chinese had very fancy things," Lessem recalls wistfully. Three weeks before the show opened in Houston, he says, "I got a call . . . They said, 'We got a better offer, we're sending it to Italy.' "

He found replacements from private collectors of Asian antiquities and the show went on - as it has in eight cities during the past nine years (Philly will be the ninth venue), losing and gaining artifacts thanks to chance encounters and shifts in geopolitics.

"We've had a whole chain of different lenders," Lessem says.

"I had things from the Hermitage [in Russia]. I had 20, 30 things. But then . . . Putin. He stopped talking to us.

"I had things from Mongolia for a while, but then they changed governments."

In 2010, a Caucasian guy wearing Mongolian robes showed up at the Genghis Khan exhibit's San Jose, Calif., opening, where he admired the antique armor and swords, Lessem says. "He walks in, says 'You've got great stuff. I've got better, frankly.' "

That one collector has since lent the show 60 artifacts from the 13th and 14th centuries - swords, helmets, bows, a whistling arrow, a saddle and some jade and fine ceramics. One marquee attraction: a sword that belonged to one of Marco Polo's guards.

"Everything I do, something great or horrible happens. Or both," Lessem says.

The mummy-nabbing charges were filed in Mongolia after a mixup with the country's new minister of culture over how long that precious artifact was allowed to travel with the Genghis Khan show. Not to worry, though: "Everything went back to Mongolia that was supposed to," Fitzhugh confirms.

Oddly enough, Lessem's loose-cannon approach is helping to fill the museum world's own gap these days - lotta gaps - as rising costs and complexities sideline cultural institutions from underwriting big shows like Genghis Khan. (The Franklin Institute produced its own 2011 "Dead Sea Scrolls" show, which now travels, and is part of a museum consortium that has some exhibits in planning.)

"He aggravates museum curators sometimes because he finds ways to do things that are not through the usual channels," Fitzhugh says. "But it's only because he can do those things that the show happened."

And Dino Don's traveling Genghis show is a good one, he says.

Good enough for the Smithsonian? "Oh, absolutely, sure," says Fitzhugh, who's a director at the Smithsonian's National Museum of Natural History. "We would have definitely taken the exhibit, if we had found a way to compensate Don." (The taxpayer-supported national museums don't charge admission.)

As you read this, Lessem's landmark Genghis Khan show is sitting in storage locally after traveling from its previous tour stop, in Vancouver.

"It's in a box - many, many boxes - in Chester," he says. The first of them were scheduled to embark for the Franklin Institute yesterday.

"The artifacts are in an undisclosed location. I just keep a couple things here. It's fun to have around the house."