Which famous marketing campaign featured mysterious symbols appearing in crop fields across multiple countries before the book's release?

The publishing world has seen some iconic marketing campaigns that transformed books into cultural phenomena. From clever promotional strategies to innovative launch events, publishers have found creative ways to capture readers' attention in an increasingly crowded marketplace. Test your knowledge about some of the most influential and groundbreaking book marketing campaigns that changed the literary landscape!

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Dan Brown's 'The Da Vinci Code' - with Fibonacci sequences and cryptic advertisements
J.K. Rowling's 'The Casual Vacancy' - with redacted manuscript pages leaked strategically
Stephen King's 'The Dark Tower' series - with cross-dimensional portals appearing in major cities
Thomas Harris's 'Hannibal' - with crop circles and strange symbols appearing in fields across Europe and the US