The labyrinth is a puzzle cache. It's a small tube where you have to solve a blind maze to open it. Don't worry, the maze is easy.
Finding it is the hard part.
In order to get to GZ, you need to look for a small trail past the park along the road. It can be hard to spot. Go down the trail, and you will reach a concrete box. This is the area of the cache.
Bring your own pen!