Disneyland Park
Opened in 1955, it is now the second most visited park in the world, behind Disney World Orlando. The actual park is known as the Magic Kingdom and is actually just 1 of 4 parks in the area. If I'm not mistaken the parks are: (Magic, MGM, Animal Kingdom, Epcot). The Magic Kingdom is just one of the four, but it is the original. So not to be missed, whether you are big or small, but if you've been to Eurodisney, it is exactly the same. It is 40 km from the center, but within the city, specifically in Anaheim.