This is one of the seven tunnels which were built in the 1880s. The purpose of this astonishing Helensburgh Tunnel was to provide a safe passage through the hills between Otford and Waterfall. But when the steam locomotives appeared, there was a need for a double lane. Given that the tunnel has a single lane, it had no further use. So, the tunnel was closed in 1920.
Once the tunnel was closed, people started visiting the place. The tunnel is a perfect combination of beauty and mystery. There are glow worms in the tunnel that light up the place in the dark. Unfortunately, the tunnel is not open for visitors anymore because it was vandalized.