A question we often get is around the difference between Disney World and Disneyland so today I thought it would be helpful to sum it up.
Disneyland is a) the original park, b) in California and c) much smaller. Walt Disney World is in Florida and considerably bigger. Then of course, from the UK, we are also fortunate enough to be close-ish to Disneyland Paris - which used to be called Euro Disney. This has the advantage of being close, but again, is much smaller than Walt Disney World in Florida.
Disneyland Resort, in Anaheim, California, is the park that Walt Disney himself imagined and over saw the creation of. It opened in 1955. These days it is made up of 2 parks. Disneyland Park is the original, quintessential Disney park, featuring Sleeping Beauty's castle as the centre piece. Disney's California Adventure is the second park. This opened in 2001. It did not initially have fantastic reviews but has under gone huge investment in recent years and is now very popular - Carsland in particular is a hit, which opened in 2012. Also within Disneyland Resort is Downtown Disney - a shopping and entertainment district, and 3 Disney hotels.
Walt Disney World
After the success of Disneyland, Walt Disney quickly realised that he was limited by the space available to him in Anaheim, and so he set out to seek an area where he could buy a significant amount of land - this was the start of the 'Florida Project' - with land bought up in secret. This was the start of Walt Disney World, which today is made up of 4 theme parks, 2 water parks, Disney Springs (shopping and entertainment district) and 28 Disney-owned hotels - with more coming from this year.
Magic Kingdom opened in Walt Disney World in 1971, having been developed by Roy Disney after Walt Disney's death. This is the park closest in nature to Disneyland Park, with Cinderella Castle at the centre of it.
EPCOT Centre opened in Walt Disney World in 1982, now named simply 'Epcot'. It is known for the giant golf ball - geosphere, which houses the 'Space Earth' ride. The park has changed in concept over the years. It is split between 'Future World' where you will find the majority (but not all) of the rides and 'World Showcase', which showcases 11 different countries.
In 1989, MGM Studios opened - which was renamed to Hollywood Studios in 2008. This park is dedicated to everything movies and Hollywood. Toy Story Land and the soon to be Star Wars land are the newest additions to Walt Disney World and are found in this park.
The final theme park, Animal Kingdom, opened in 1998. This is dedicated to animals, nature and conservation and it's pivotal point is the humungous Tree of Life.
Also in Walt Disney World, you have Blizzard Beach and Typhoon Lagoon water parks, and Disney Springs (formerly Downtown Disney), which is made up of shops, bars and restaurants.
So you're probably getting the jist - Walt Disney World is huge. People think we're crazy that we go so often, and we usually don't venture out of Disney at all, but most genuinely don't realise the size of it. The whole thing is 40 square miles - approximately the size of San Fransisco, or twice the size of Manhattan. You really can go for 2 weeks and do something different every day, if you want to. However, a trip to Disneyland, in California is different. While we easily could spend two weeks there, we wouldn't - even for big Disney fans we recommend spending 3-5 days there and then spend time exploring some of the other amazing destinations in California. Whichever you go to, you're going to have a fantastic time - but Walt Disney World is a destination in its own right.