Walk through the linden path to a small bridge in the reserve park. At the other end is a tunnel formed by volcanic lava flowing down the mountaintop. This is the famous "Thurston lava passage" (Thurston Lava Tube ). It is said to have a history of 500 years, when hot magma passed through the mountains, and as the top and sides of the surface cooled, the magma flow formed a shell, and the lava continued to flow to the coast, so it became a hollow lava tunnel. After years of change, the tunnel is full of green sheep teeth. The hole is large, wet and cool.