Where can you download full Sims 3 worlds complete with houses and workplaces?

I know you can download worlds from the Sims 3 website and places like thesimsresource.com, but how can you get worlds that are full with houses and workplaces? If you don't understand what I'm asking, please ask me to clarify. Thanks!
Update: Maybe you have to have World Adventures, which I don't???
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