In his column today at the Jerusalem Post, Wayne Stiles traverses the length of the Western Wall underground, recommending this as an ideal way to get more out of your day in Jerusalem.
Traveling though these excavated tunnels a few weeks ago, I saw several discoveries made in recent years. The steps of a very large mikveh (ritual bath) are visible about 10 meters below the modern path (noted previously on this blog here).
Last month, they finished excavating and opened up to visitors a new portion of the Struthion Pool.
This is located to the east of the part of the pool that once served as the terminus of the tour.