That is such an excellent book. If you like it, you may also enjoy "Foucault's Pendulum" by Eco as well.
When i read The DaVinci Code years later, it feeled like a very decaffeinated (really "de-lots of things") version of Foucaults Pendulum. It also feels like it spawned this sort of genre of history-mystery-conspiracy-airport-and-beach-novel.