Dan Brown's novel "Angels & Demons" mixes Christian symbolism, secret societies, and pagan signs into a thriller set largely in Rome, and this film sends historians, art scholars, and theologians to check the book against the record. They walk the same ground as protagonist Robert Langdon, from St. Peter's Square to the Pantheon, tracing which landmarks, artworks, and rumored tunnels under the Vatican are real and which Brown invented or rearranged for plot convenience. The Illuminati, long dissolved as a historical group, get separated from the shadowy conspiracy Brown revives for his story. Interviewees weigh in on the accuracy of the novel's claims about Bernini's sculptures and the Church's history with science, and the film uses recreations to place viewers inside the Vatican's corridors and Rome's older streets. The result works as a companion piece for readers curious how much of Langdon's Rome actually exists outside the book's pages.