The chapel is featured prominently in the novel and the subsequent movie adaptation. It's described as containing cryptic symbols and hidden secrets, which the characters in the book believe are clues to the Holy Grail. While the chapel itself is a real, beautifully decorated building with a fascinating history, the specific secrets and symbols mentioned in the book are fictional.
The novel's popularity led to a significant increase in tourism to Rosslyn Chapel, with many visitors seeking to find the "Da Vinci Code" clues in the architecture and stonework.