Dan Brown writes novels. Fiction. It says so right on the spine of the books. And yet he's able to weave enough historical details into his flights of fancy that it's nearly impossible to tell what he uncovered through exhaustive research, and what he just made up.

"Angels & Demons," the new movie based on Brown's first Robert Langdon novel, just opened at the top of the box office charts around the world. But like "The Da Vinci Code" before it, viewers came out of the theater wondering just what in the story was real. While many of the story elements are rooted in historical truths, most of the specifics are straight out of Dan Brown's imagination.

THE ILLUMINATI
A shadowy organization known as "The Illuminati" did meet in secret with the goal of overthrowing a religious figurehead. But it was actually established in Germany in 1776, not in Italy nearly two centuries earlier as stated in "Angels & Demons." Their intention was to overthrow the Catholic monarchy of the Kingdom of Bavaria and replace it with a secular republic. Contrary to the movie, its members were mostly bureaucrats and lawyers, with few if any scientists in the mix. And their ranks certainly didn't include the great sculptor Bernini, who died in 1680. The police uncovered their plans, their leader fled the country, and the Illuminati died out by 1790.

ANTIMATTER
CERN (Conseil Européen pour la Recherche Nucléaire) is the world's largest particle physics laboratory, where the World Wide Web began and where the Large Hadron Collider is set to start smashing protons this summer. And they have produced antimatter; in fact, they do so on a regular basis. But CERN officials say that in the last 20 years, they have produced about 10 billionths of a gram. Collectively, that would be about as explosive as a firecracker. For a weapon as destructive as a nuclear bomb, you'd need a half a gram of antimatter, which would take about 2 billion years to manufacture.

THE PATH OF ILLUMINATION
In the book and movie, Robert Langdon deduces that Bernini left clues to the directions to the Illuminati's secret meeting place in Rome within his statues. Inscribed in "Diagramma," a secret text by Galileo (invented by Brown), is a poem by John Milton (actually Brown) that holds the instructions to finding the path. There are four signposts, corresponding to the four natural elements, and the poem concludes with the line "Let angels guide you on your lofty quest." Brown gets some details right and many others wrong about each of the four stops.

"EARTH" - Chigi Chapel
In the St. Maria del Popolo Church, you will find the Chigi Chapel, which was designed by the Renaissance master Raphael. Within the chapel there are two marble pyramids, and there are two statues by Bernini. There is also a "demon's hole," which is sealed now, but does lead to an underground crypt. One of the statues, "Habbakuk and the Angel," does feature an angelic figure pointing in a south-westerly direction towards the Vatican. Of the four "Altars of Science" laid out by Brown, this one is the closest to reality as presented in the book and movie.

"AIR" - St. Peter's Square
Around the obelisk in the center of the square is the "Wind Rose," a circle of 16 elliptical marble reliefs -- not just one as in the book -- labeled with the names of the directions of the wind. Langdon interprets the marker labeled "West/Ponente" as his guide of where to go next. One problem: Bernini designed St. Peter's Square, but not these markers, which were added around 1852, over 170 years after his death.

"FIRE" - The Ecstasy of Saint Theresa
The church of Santa Maria della Vittoria does lie to the west of St. Peter's Square, and inside you will find Bernini's masterpiece "The Ecstasy of Saint Theresa." That's about where the similarities to reality end. The statue wasn't moved to the church because of Vatican protests; it has always been there. Also, the church is much smaller in reality than what is shown in the movie. Nearly all of the interiors in the movie were built on soundstages in Los Angeles. Most notably, the angel on the statue holds an arrow, and Langdon follows the point of the arrow southwest to his next location. But in reality, the angel's arrow points northeast.

"WATER" - The Fountain of the Four Rivers
Langdon arrives at the Piazza Navona, site of Bernini's "Fountain of the Four Rivers," just in time to see the Illuminati killer drive up in his van and dump his final kidnapped cardinal into the water. But vehicles are blocked from driving in the piazza, and the fountain is not much more than a foot deep. And there are no air hoses along the bottom to produce bubbles (or keep a bound clergyman alive underwater). Langdon uses the dove on the obelisk that rises out of the fountain to point his way, and again it's pointing in the wrong direction.

THE CHURCH OF ILLUMINATION
The trail leads Langdon to the Castel Sant'Angelo, the circular structure built originally as a mausoleum and used by the Church as a fortress and prison. A statue (not by Bernini) of an angel stands at the top, pointing his sword downwards to where the villain hides. Of course, the still-existing jail cells where he held the cardinals are a feature of the tour that services hundreds of visitors a day, which might have been a giveaway. At least in the movie they correct Brown's mistake in the novel. He places the passageway from the Castel to the Vatican as being underground, and in the film you see Langdon run along the top of the wall between the two.

"Angels & Demons," both the novel and the movie, take great liberties with the truth to tell their story. And why shouldn't they, really? Brown prefaces his book by writing, "References to all works of art, tombs, tunnels, and architecture in Rome are entirely factual." He might be stretching the truth as much there as anywhere else in the book. Still, the book sold millions of copies, and the movie is raking in cash. But if you're in Rome and would like to follow the Path of Illumination for yourself, you can take the Official Angels and Demons Tour. You won't unravel a centuries-old mystery, but you will see some amazing and timeless works of art.