Get ready to mark your calendars for some special days that only the BIGGEST Disney fans know about!

Sure, there are plenty of ways to celebrate holidays like Halloween, Christmas, and St. Patrick’s Day in the Disney parks. But there are some holidays that only Disney superfans know about! Here are some special Disney days that you won’t find pre-printed on your planner.

Disneyland’s Opening Day Anniversary — July 17th

Disneyland first welcomed guests on July 17th, 1955. And thus, Disney’s pioneering of the theme park industry began!

Believe it or not, the grand opening was actually a bit of a disaster (Seriously. It’s often referred to as “Black Sunday!”). Several iconic attractions weren’t ready in time for the opening, water fountains around the park weren’t working yet due to a plumber’s strike, fresh asphalt and scorching temperatures turned Main Street, U.S.A. into a mess with women’s heels sinking into the street, and counterfeit tickets packed the park with uninvited guests.

But luckily Walt and his team persevered, ironing out the initial blunders and surpassing one million visitors within the first seven weeks of operation.

There are several ways guests can mark this special moment in Disney history. Milestone anniversaries are often celebrated with special snacks, merchandise, and decor.

Since Disneyland is a “locals park,” with much of the attendance coming from guests who live nearby, marking the anniversary with a trip to the park is a special occasion for many Disneyland fans!

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Walt Disney World Opening Day Anniversary– October 1st

Walt Disney World celebrates its opening day on October 1st, as Magic Kingdom first welcomed guests on October 1st, 1971.

Eleven years later, this date became even more significant, as EPCOT first opened on October 1st, 1982.

Similar to Disneyland, Disney World milestone anniversaries are celebrated with special snacks, merchandise, decor, and entertainment. And these goodies have definitely been at the top of our minds lately, as Disney World prepares for its 50th-anniversary celebration later this year!

The celebration, which Disney is calling “The World’s Most Magical Celebration,” is set to kick-off on October 1st, 2021. But if you can’t make it right away, don’t worry — it’s slated to run for 18-months following the anniversary!

There are a TON of festivities that have been announced for the celebration, including makeovers for the park icons…

…the grand opening of Remy’s Ratatouille Adventure in EPCOT…

… and new costumes for Minnie and Mickey!

And it’s already shaping up to be a BUSY day in the parks on October 1st — Disney Park Passes for Magic Kingdom are currently completely booked up, although it is possible that Disney may release more availability closer to the date as they have in the past.

We’ll be on the lookout for any additional details and announcements about the upcoming festivities as the 50th-anniversary approaches, so stay tuned for all of the latest info!

Here’s Your Guide to the Walt Disney World 50th-Anniversary Celebration!

Opening Day of Disney’s Animal Kingdom Anniversary — April 22nd

It’s significant that Disney’s Animal Kingdom opened on the same day as another holiday — Earth Day. The park’s opening date of April 22nd, 1998 ties into its goal of conservation.

Typically, Animal Kingdom’s anniversary is celebrated with the annual Party for the Planet, which has featured talks from Disney Imagineers, special character experiences, unique photo ops, and more.

And as with the other anniversary events, special snacks and merchandise have also been known to pop up in the park in honor of the “holiday.”

Even though April 22nd might stick out already as a holiday, it takes on a whole new meaning to Disney fans!

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Dapper Day

When Disneyland first opened, it was commonplace to see women in dresses and petticoats and men in their Sunday best. Today, it might look a little odd to see folks dressed to the nines on a hot day in Disney World, but it happens! Dapper Day is a celebration of fun, vintage style, and it’s a great excuse for Disney fashionistas to get all dressed up for a trip to the parks!

There is typically a spring and fall outing in both Disney World and Disneyland, although the exact dates and parks can change from year to year.

If you’re in need of an outfit to celebrate, you might even be able to find the occasional Dapper Day pop-up shop for all your fashion needs!

So, if you happen to spot a group of impeccably dressed guests strolling through the parks on your trip, you may have just stumbled upon a Dapper Day outing!

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Mickey Mouse’s Birthday — November 18th

Walt Disney himself once said, “I hope we never lose sight of one thing – that it was all started by a mouse.” And Disney fans around the world have continued to recognize Mickey’s legacy by celebrating his “birthday” on November 18th.

The Disney parks make it easy to celebrate the main mouse’s birthday, with special snacks, merchandise, and promotions.

And there’s an extra-special Imagineering detail in the queue for Under the Sea — Journey of The Little Mermaid in Magic Kingdom that only reveals itself on Mickey’s birthday.

Part of the rock formation in the queue is carved so that the sun will shine through onto the base of a wall at the perfect angle to form Mickey’s head ONLY on November 18th each year at noon. Now that’s an elusive Hidden Mickey!

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Adventureland Day — First Sunday in March

Looking for an excuse to dress up in your best Enchanted Tiki Room, Jungle Cruise, Indiana Jones, or Tarzan attire? Well then, Adventureland Day is the holiday for you!

On the first Sunday in March, Adventureland Day participants dress up in garb inspired by their favorite attraction from the land to celebrate the magic it inspires. Since this event is a fan-made tradition, it still have a very fun home-grown feel to it. Scavenger hunts are often created, as well as planned meet-ups and photo ops.

From colorful Tiki Room birds to treasure hunting explorers, there’s definitely plenty of inspiration to pull from! If you want to follow when the next day rolls around, you can check out their Facebook page here!

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Just because these “holidays” don’t come pre-loaded on your average calendar doesn’t make them any less important for Disney superfans! These holidays are a great excuse to show some love to your favorite character, attraction, or entire park. Plus, you might even get to enjoy a special treat, new merch, or exclusive entertainment as part of the celebration. Now that’s REALLY something to get excited about!

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Which of these Disney holidays have you celebrated? Let us know in the comments!