Theme parks are core to the business model of American media giant the Walt Disney Company. Last year its 11 parks around the world provided nearly a third of its $45 billion revenue and 20.7% of its $10.7 billion operating profit. New research has uncovered some of the secrets to this success.

It reveals that Disneyland Paris, which was once seen as a poor relation to its bigger brothers in the United States, is now one of the top performers. In fact, it has generated more than $700 million in profits since opening in 1992 and made $85.7 million last year alone.

The driving force behind Disney’s theme park profits is its scale. Saying that Disney runs the world’s busiest theme parks doesn’t do justice to its status. In total they attracted 132.5 million guests last year according to the 2013 global attractions attendance report produced by industry monitors AECOM Economics and the Themed Entertainment Association (TEA). The total was more than double the 59.8 million who visited Disney’s closest rival, British business Merlin which runs the Legoland and Sea Life parks.

Disney’s other major competitor, Universal Studios, is third in the global attendance rankings but has a fraction of its visitor numbers. Last year Universal attracted 36.4 million guests which may sound like a lot but, to put it in perspective, it is just under double the 18.6 million who visited Disney’s fairytale-inspired Magic Kingdom in Florida making it the world’s most popular park.

Indeed, all but one of the ten most-visited parks worldwide are run by Disney with the exception being Universal Studios Japan which had 10.1 million guests last year.

The reason why Disney’s parks are so popular stretches back to the 1950s. Legendary animator Walt Disney invented modern-day theme parks with the opening of his first Disneyland park in California in 1955. His motivation was the lack of entertainment options available to him and his two young daughters.

The amusement parks of his era had few rides that parents could enjoy with their children and they were often dirty and unsafe. Disney changed that by integrating his rides with stories which had become famous in his blockbuster movies. It marked the start of a process which now fuels the profit-making power of Disney’s parks.

No longer was a roller-coaster a winding track in mid-air. Instead, Walt’s version was a runaway mine train integrated into a mock-up of the mountains from Bryce Canyon National Park in Utah.