On July 17, 1955, the world was introduced to a new force in family entertainment and vacations: Disneyland. Though many critics predicted that it would fail, the park's millionth guest passed through the gates just seven weeks after its debut. Since then, Disneyland has set the standard for the theme park industry, eventually paving the way for nearly a dozen more Disney parks around the world.

A second park, Disney California Adventure, was added to the Anaheim complex in early 2001, delivering a completely different experience. Here, on the resort's 60th anniversary, we take a look at some of the major differences between the two.

Here, we'll break down:

• The difference in size between Disneyland and Disney California Adventure
• The different themes at Disneyland and Disney California Adventure
• Different restaurants at Disneyland and Disney California Adventure
• The best attractions and rides at Disneyland and California Adventure
• Entertainment, nightlife, and fireworks at Disneyland and California Adventure

1. Size & Attendance
The entire complex that comprises the two theme parks, three hotels, and the Downtown Disney District is 500 acres. Among those acres, Disneyland claims 85 and Disney California Adventure takes up another 72. And, while Disney won't release daily attendance numbers, park experts estimate that the Happiest Place on Earth has at least 44,000 visitors each day, according to the Los Angeles Times. 

2. Themed Areas
Guests get their initial taste of Disneyland as they enter onto Main Street, USA: the first of nine themed sections in the park. Others are Adventureland, Frontierland, New Orleans Square, Critter Country, Fantasyland, Mickey's Toontown, Tomorrowland, and Star Wars: Galaxy's Edge. Sleeping Beauty Castle serves as the park's main centerpiece. 

At Disney California Adventure, you can meander through seven themed areas: Buena Vista Street, Pixar Pier, Paradise Gardens Park (previously known as Paradise Pier), Grizzly Peak, Pacific Wharf, Hollywood Land, and Cars Land. Buena Vista Street sets the stage for what the rest of the park has in store. (Fun fact: Buena Vista Street is home to a reproduction of the Carthay Circle Theater, the venue where Snow White and the Seven Dwarfs, Disney’s first animated film, hosted its premiere in 1937.) California Adventure has its own statue of Walt Disney and Mickey Mouse, which depicts Walt arriving in Los Angeles in 1923.

3. Dining
The parks each have around 30 quick service and table service restaurants, where you can snack on Mickey pretzels and lobster nachos or sit down for duck wings and shrimp scampi. While Disneyland has been alcohol-free since its opening, Olga's Cantina, which part of the new Star Wars: Galaxy's Edge, serves alcohol to those of age.

4. Big-name Attractions
Classic attractions abound at these two parks. Even if you’ve never been a visitor there, chances are you’ve probably heard the name of one of their world famous rides at least once.

Did you know the first Pirates of the Caribbean film is based on the ride of the same name at Disneyland? The popularity of the film series has since inspired some additions to the park. Other headlining attractions at this park include Splash Mountain, Dumbo the Flying Elephant, Space Mountain, The Haunted Mansion, Matterhorn Bobsleds, and, of course, It's a Small World. 

It may not be as old as Disneyland, but California Adventure is also home to some classic rides, including Pixar Pal-A-Round  (Mickey’s Fun Wheel), Soarin’ Over California, Radiator Springs Racers, Toy Story Mania! and The Little Mermaid: Ariel’s Undersea Adventure. Here, you'll also find an an inverted rollercoaster,
Incredicoaster (formerly known as California Screamin’).

5. Nighttime entertainment
Entertainment goes well into the evening hours at Disneyland Resort, with stage shows and street performances to 3-D productions and parades that dazzle guests.

At Disneyland, firework displays light up the night. There's also Fantasmic, which features your favorite Disney characters, floats, puppets, and music), as well as Disney Villains Dance Party. Seasonal entertainment include Halloween Screams with Fireworks and Dia de Los Muertos.

At California Adventure, you won’t want to miss the World of Color show, which incorporates mist, water, color, and projection to showcase the incredible imagination of Walt Disney. The visuals are impressive, but equally mind-boggling are the logistics behind it: The fountains shoot water up to 200 feet in the air, casting a 19,000-square-foot aqua projection screen.