How to apply collision detection to a Circular (round/curvy) Labyrinth

We're using Unity 2017.30f3 and we're building a labyrinth game.
(We are remarkably new users and working on a project to learn Unity)

We built the labyrinth using this image: Rounded labyrinth. The image is at the bottom of the post as well.

Currently, there is no collision on the walls of the labyrinth. Everything I have read about adding collision seems to assume rectangle shapes (or angular walls) or complex shapes.

How do we make our walls solid and stop the player / camera from passing through them? Reading about mesh colliders leads me to believe we have to go through inch by inch and map each surface to basically build the maze as angular meshes.
Details: We built the maze by modeling 8 concentric circles and adding/removing sections to create the labyrinth.