Walt Disney Co. unveiled Wednesday a major multi-year makeover plan for California Adventure, in an effort to boost lower-than-expected business at the theme park, which has been living in the shadow of neighboring Disneyland since its opening six years ago.

The plan, expected to cost over 1 billion U.S. dollars, would give California Adventure more clearly defined theme sections like Disneyland, which opened to rave reviews in 1955 in Anaheim, the resort town near Los Angeles.

"The success of the Disneyland Resort over the past few years provides us with both the opportunity and the need to invest for growth, to enhance and expand the experience for our guests and attract new visitors," Disney CEO and President Bob Iger told a news conference here Wednesday.

He said the expansion plan is a reflection of Disney's belief in the bright future of the Disneyland Resort and its continuing commitment to grow the Anaheim Resort Area as a world-class tourist destination.

California Adventure, opened in 2001 under former Disney CEO Michael Eisner as part of the resort, has failed to live up to corporate expectations. Critics in the board of directors seized on the project's poor performance when they campaigned to oust Eisner in 2004.

The younger theme park, which is loosely focused on the Golden State, attracted fewer than 6 million visitors last year, short of the 7 million the company anticipated and a far cry from the 15 million people who bought tickets to Disneyland.

Disney officials said the makeover plan would bring more of Walt Disney into California Adventure and make it more like the "Happiest Place on Earth" next door.

Among the prominent additions being planned are a new Cars Land inspired by the Disney/Pixar animated film "Cars," Toy Story Maniaand the Little Mermaid, also based on Disney films.

A new entrance plaza will be a visual icon in the tradition of the great entertainment palaces of Los Angeles, officials said. The plans were inspired by Los Angeles' historic Carthay Circle Theater that premiered "Snow White and the Seven Dwarfs" in 1937.

The plaza will also house a "Walt Disney Story" attraction featuring an interactive tribute to Walt's California experiences and his entertainment legacy.

According to Disney officials, the initial redevelopment, which also included Downtown Disney and the Grand Californian hotel, cost about 1.4 billion dollars.