SOMETHING IS WRONG in the Gallery of Rumbling.

A look of bemused disorientation is probably natural on the face of any Frenchman who finds himself in a non-smoking environment 200 feet under the earth. But the puzzled expressions of the Auvergne families standing to my left—French provincials who've paid $17 a head to see the sights at Vulcania, a new volcano-themed $100 million underground entertainment park—betray a more serious unease.

Is it panic, perhaps? Because it's really loud in here: Hidden speakers are blasting a thunderous soundtrack as video images of flame-orange magma flicker across the faces of huge, flat boulders, the kind you see separating the rhinos and elephants in metropolitan zoos.

But the Auvergnats seem oblivious to the noise and the neon fissures beneath their feet. They live in real volcano country, after all. Several stories up from where we stand, the beautiful Parc Naturel Régional des Volcans unfolds in every direction, 1,600 square miles dotted with 80 lava peaks rising to 6,200 feet. Dormant for the past 6,000 years (but not forever), these peaks provided stone for the hundreds of black cathedrals and castles in this area, which is sandwiched between Provence and Bordeaux in central France.

No, the problem goes more like this: The Auvergne has never had a theme park before, so the locals don't quite have the moves down. In particular, the policy of American-style unlimited access to all attractions seems to be causing serious confusion.

"They want to know 'where is room one, where is room two?'" says Stéphanie Boulliaud, Vulcania's peppy 28-year-old PR spokesman. "They don't understand that they can visit everything 20 times if they want. That is something that is very American, but not very French."

Also known as the European Park of Vulcanism, Vulcania is the pet project of former French president Valéry Giscard d'Estaing. A longtime Auvergne booster—his grandparents lived there, and he attended school in the capital city, Clermont-Ferrand, where he also owns a home—Giscard wants to lure more tourists to the economically depressed region. His ambitious plan, now complete, called for a 90-foot titanium-lined "volcanic cone," simulated lava flows, 3-D films, and hands-on exhibits to promote volcanology.

It all sounds pretty tame by U.S. theme-park standards. But this is France, a country whose citizens greeted the coming of EuroDisney 13 years ago by literally chucking eggs at visiting Disney chief Michael Eisner. The 1992 announcement of plans to build Vulcania touched off a full-blown culture war, culminating in anonymous death threats against some of Vulcania's backers—allegedly made by radical environmentalists who didn't want construction disrupting the local scenery—followed by retaliatory searches of suspects' homes.