How do 3D side view backgrounds?

I’m learning ue4 by creating a 3d sidescrolelr game, and i’m not sure how the background should be.
I’ve tryed to place some mesh far away on background, but there is not any distance effect, only size, it’s possible to add some fog affecting only distant effects, so they looks like they are far away?
Something like this:

In that image the distance effect is very obvious.
How could i do this?

You could use an Exponential Height Fog. Increase it’s intesity to .8 - 1 and set the distance depending on how you set the level.

Thanks!! works like a charm :smiley: