J.K. Rowling's Harry Potter turns 20 | See how to celebrate in Atlanta

It’s enough to make a Muggle feel downright ancient.

(Or maybe just young all over again?)

On Monday, Harry Potter turns — gulp — 20.

It was two decades ago — June 26, 1997 — when first-time novelist J.K. Rowling’s little book about the orphaned boy who’d grow up to become the GOAT (Greatest of All Time) wizard was published in England. That’s when a few (really) readers got their first glimpse into the fantastical world of Hogwarts and Hagrid and Death Eaters and Dobby the House Elf.

No one suspected then that “Harry Potter and the Philosopher’s Stone” would launch a seven-book, eight-movie, one hit play and several theme parks phenomenon that would culminate in (spoiler alert!) the evil Voldemort’s demise. And arguably revive reading, considering over 450 million “Potter” books have been sold in 79 different languages to date.

Indeed, the book wouldn’t even be published here for over a year. Scholastic released it with a slightly altered title, “Harry Potter and the Sorcerer’s Stone,” in September 1998. Some 160 million sold books later, Scholastic is gearing up to celebrate that anniversary in a big way next year.

Related video: 7 things you didn’t know about the Harry Potter book series

But its “Pott”-y time right now in the U.K. and even a few parts of the U.S., like Cobb County. Here’s a “Happy Harry-day” guide to it all (with apologies to Rowling for our mangling of some of her books’ titles):

Harry Potter and the Chamber of Secret Facts

British publisher Bloomsbury initially printed only 500 copies of the first book. Some 14 months later, the first print run for "Sorcerer's Stone" in the U.S. was 50,000 copies.

"J.K. Rowling" is a pen name of sorts. The publisher felt a book by a female author would have less appeal for Harry Potter's initial target audience of young boys. Joanne Rowling didn't have a middle name — the "K" is for her grandmother, Kathleen.

Long before the hit London play "Harry Potter and the Cursed Child" (it's coming to Broadway next spring), Michael Jackson once approached Rowling about making a Harry Potter musical. She turned him down. The King of Pop is also directly responsible for there being no zombies among the books' many otherworldly creatures: "I'm part of the 'Thriller' generation," Rowling wrote on her website Pottermore in 2014. "To me, a zombie will always mean Michael Jackson in a bright red bomber jacket."

Rowling made up the name "Quidditch" after filling five notebook pages with words beginning with "Q." She came to dislike her pretend wizarding sport — "There is a limit to how many ways you can have them play Quidditch together," she said in a 2005 interview — but this year "Quidditch" was the second Potter word added to the authoritative Oxford Dictionaries ("Muggles" made it in 2002).

Fantastic Celebrations and Where to Find Them

"Harry Potter 20th Anniversary Celebrations" are going on all over the U.K. and parts of Europe on Monday, according to Bloomsbury's interactive map (www.harrypotter.bloomsbury.com). Wanna go? Each entry has info on when and where to show up, wizarding-heavy dress codes and what to expect, like "magic and mayhem" or "Exploding Chocolate, Bertie Botts beans & Butter beer!" (that one starts at 11 a.m. in Bruges, Belgium).

Among the several U.S.-based celebrations on the map, one stands out: It's at the Ole Miss Bookstore in Oxford, Miss. "This party is in line with the U.K. release date of 'Harry Potter and the Sorcerer's Stone,' which marked the start of the iconic journey that a generation grew up taking with Harry," trade manager Katie Wallace wrote via email about why Harry's being feted in a college bookstore. Fittingly, all attendees get a Hogwarts acceptance letter. 5-7 p.m. Monday. Free. 1111 W. Jackson Ave, University, Miss. 662-915-7137, ole-miss.bncollege.com.

In Georgia, Cobb County's libraries are going potty for Potter. From 10 a.m. to 9 p.m. Monday, Mountain View Regional Library will host "Harry Potter: A Magical Twentieth Anniversary Celebration." Participants can "attend Hogwarts, stroll through Diagon Alley, and hang out in Hogsmeade." Come in costume, take part in quizzes, Quidditch and more. 3320 Sandy Plains Road, Marietta. 770-509-2725, www.cobbcat.org.

Meanwhile, it's "Harry Potter Week" at Switzer Library in Marietta. From June 23-30 (library closed Sunday), the main Cobb branch hosts all-day (11 a.m.-6 p.m.) activities, including wand making, "sorting" and photo ops. On Saturday (June 24), there's a "come dressed in your Hogwarts finest" screening of "Harry Potter and the Sorcerer's Stone." The big day, Monday, culminates in Harry Potter-themed games starting at 5 p.m. Also, you can catch the last session of "Hogwarts: A Summer Semester," featuring a Harry Potter read-aloud and crafts, from noon to 2 p.m. Thursday. 266 Roswell St., Marietta. 770-528-2320, www.cobbcat.org.

Pottermore … and more

Check out these upcoming events for more ways to say “Hurray for Harry!”

The Wizarding World Book Club. Launches Monday on Pottermore.com, Rowling's official news, entertainment and digital publishing site. Beginning with — what else? — "Harry Potter and the Philosopher's Stone," the club will read books together and examine a different theme each week, such as "Magic and the Muggle world" and "Friendship." Sign up at www.pottermore.com, follow/discuss on twitter at @wwbookclub.

Harry Potter movie "marathon" at the Fabulous Fox Theatre. See all eight movies in order on two consecutive weekends in August as part of the 2017 Coca-Cola Summer Film Festival. Starts at noon Aug. 5 with "Harry Potter and the Sorcerer's Stone" and wraps up with "Harry Potter and the Deathly Hallows — Part 2" at 4 p.m. Aug. 13. Discounted ticket packages, including "full movie eight-pack" and multiple films packages, available. Fox Theatre, 660 Peachtree St. NE, Atlanta. FoxTheatre.org.

"Harry Potter: A History of Magic." Opening in October at the revered British Library in London, this exhibition will combine "centuries-old British Library treasures" with original material from Rowling's and Bloomsbury's archives to explore magic, wizarding and even medieval manuscripts and early printed books whose depictions of magical creatures may have inspired characters in the Potter books. Oct. 20, 2017-Feb. 28, 2018. For information or to purchase tickets, visit www.bl.uk/harry-potter.

Atlanta Symphony Orchestra performs "'Harry Potter and the Sorcerer's Stone' in Concert." See the film in high-definition on a giant screen as the renowned ASO performs every note from John Williams' Oscar-nominated score. Nov. 30, Dec. 1-2. $59-$159. Atlanta Symphony Hall. 1280 Peachtree St. NE, Atlanta. 404-733-4900, www.atlantasymphony.org.