Is it possible to have a hidden landscape that can be toggled on/off?

Been using Game maker studio to learn coding, moving a project of mine from 2D to 3D using Ue4 - starting a fresh but with the same designs and mechanics.

In my GM project I had a landscape and with a keyboard input, a second landscape would appear, revealing new areas, hidden items etc.

This was easily done by toggling certain objects on/off

However now I’m using 3D, some of my concerns with landscape tool is how would a user toggle aspects of the landscape?

For example:

Landscape Base: This is the base layer, its constant, a heightmap with no material, so the mould.

Landscape 1: Has multiple materials, mountains, hills, rocks, sand. Pretty much like a wasteland.

Landscape 2: Has rivers, foliage, atmosphere etc… Ontop of the rest

Landscape 2 is the main viewable land the player sees. When a keyboard input is pressed, this landscape becomes hidden and
now the player only sees the barebones of Landscape 1.

Think I’ve got an idea how to do this, but completely new to this software and don’t want to dive into this without planning out
various concepts and ideas that worked on a 2D project.

I suppose the main question here is, what’s the optimal way to accomplish this with Ue4?