How many Harry Potter theme parks are there?

There are currently two Harry Potter theme parks:

* The Wizarding World of Harry Potter at Universal Orlando Resort (Florida, USA)

* The Wizarding World of Harry Potter at Universal Studios Hollywood (California, USA)

There are also two smaller areas themed to Harry Potter:

* The Wizarding World of Harry Potter at Universal Studios Japan (Osaka, Japan)

* Harry Potter: Magic at Play at Warner Bros. Studio Tour London (London, UK)

So, depending on how you define "theme park," there are either two or four Harry Potter-themed attractions.