Hundreds of Harry Potter fans gathered in Kings Cross, London today for a milestone date. September 1st 2017 marks the date in the books when the epilogue to Harry Potter and the Deathly Hallows takes place with the title character's son, Albus Severus Potter, departing on a train from the London station for Hogwarts.

Whether you were a kid anxiously awaiting the midnight release of J.K. Rowling's latest edition of the "Harry Potter" series or that brave parent carrying armloads of memorabilia, it's no secret that Harry Potter is ingrained in both pop culture and our wallets. But do you know just how much the brand is worth? 

Hint: You're already looking at $7.7 billion, and that's just book sales, according to CNBC. The film franchise generated another $7.7 billion in revenue.

Both the first film (2001's "Harry Potter and the Sorcerer's Stone") and the last (2011's "Harry Potter and the Deathly Hallows: Part 2") broke the opening weekend record at the time of release, and "Deathly Hallows: Part 2" is one of the highest-grossing films of all time with $1.3 billion in worldwide box office receipts. In fact, seven of the eight films in the franchise are among the top 50 films ever worldwide, with "Prisoner of Azkaban" the only outlier (and not far behind at No. 65).

Overall, the "Harry Potter" franchise is the third-largest of all time at the box office, behind only the Marvel Cinematic Universe and "Star Wars," according to Box Office Mojo. The franchise was so lucrative that it inspired a spinoff film, last year's "Fantastic Beasts and Where to Find Them," which grossed $814 million around the world. A sequel is scheduled for November 2018, as "Harry Potter" is truly the property that keeps on giving.

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