75 vertices in Edit mode, 1.4 million in Object mode I'm taking a 3D modelling course at uni (it is obligatory). I don't have any experience with it, let alone interest. 

I had to make a model of a sculpture, and when I sent it to my professor, they warned me I had over a million of vertices, which would be hard to process.

Using answers I found here, I reduced the number to 75. Not sure how it worked, but I used Limited dissolve.

Object mode still shows the 1.4 M vertices. What do I need to do?? I don't understand any of this.

Here is the model: https://www.dropbox.com/s/aszflttj5vzck7y/model.blend?dl=0

Cheers.
In your model there are a lot of duplicates of the same model. They are inside in each other. 

Select the objects you need (left click while holding the Shift button). Then invert the selection (Ctrl + i). Then delete all extra objects (X)