what examples can you give about growing salads indoors?

One striking example of growing salads indoors was the project "Square Roots" from Kimball Musk.

great, what's the purpose of this project ?

Project objective: to create ten vertical farms inside sea containers.

Could you clarify what is the area of this farm ?

I do not know exactly ,but in my opinion the area of each such farm will be 29 square meters.

And on the basis of what technologies will these farms work?

Vertical farms will work on technologies developed by start-up companies ZipGrow and Freight Farms.