Load Unity Levels at Runtime

I am trying to achieve this in my project. Let's say, I want to have many different worlds in my game. But each of those levels will surely eat up some memory. As you keep adding scenes, it's impossible to satisfy the Apple Store maximum 100 MB requirement for iOS apps. How do I actually export Unity worlds and load them back in at runtime?

Example: We have a character, he wants to explore different cities. It's impossible to add all those cities inside one app. And worst of all, I might want to be able to add new city levels to my server so that users can continue exploring new ones while the 3D design team keeps adding on cities. The good thing is that, those scenes are irrelevant to the base Unity project. The character is just a first person model that does not have any ties to any of the cities. So, the city levels can actually be independent of the Unity project.

Of course, if I wanted one level, or two, or even three, that's a different story. But exploring Paris is not similar to exploring Beijing, and there are too many cities to still hold that 100 MB limit.

I hope what I am trying to do makes sense. I just don't understand how to export such world levels and import them back. Is Unity FBX exporter good for this purpose? THere's an asset for FBX importing as well.

Thanks.

Hope to hear from you soon...

 

Asset bundles.

 

Joe, thanks for replying. I do know that you can load scenes using Asset bundles. However, do you have the option of loading the assets you need? For instance, I want to load Paris. But I don't want to load London. How do I achieve that through Asset Bundles. Let's say, I have 100 cities, is it possible for the user to select and load 10 cities that he wants? Later on, if he decides to load 5 more, can it be achieved through Asset Bundles? Thanks.