Cycles - How can I make a sphere see through? How can I make a sphere see through like this:

https://sketchfab.com/models/f38fd38470c3496cb7a9f5a76fae41a1

I tried the normals trick (flip the normals so they face toward the inside of the sphere) and I tried to use the transparent shader (connected node to surface input), but neither worked.
Could anyone give me some advice?
I think you are asking for front face culling. I have made the material in cycles since you didn't specify which engine you are using. The sphere contains a blue cube and the front faces of the sphere are not rendered. If it appears black you need to set up a shadow-less light or place lights on the inside of the sphere.

The setup: