Did you know that deep down inside the tunnels of the London Underground, in hidden holes in the tunnel walls, there are families of mice, waiting for a little white bird. Their sweet singing floats through the tunnels like ghosts and the legend of the garden is a living whisper in the darkness. So next time you are standing on the platform of a London Underground station, peering into the tunnel and waiting for your train. Listen carefully, really listen, and you might just hear them.