At this point we enter a very long, straight passage. It is known as "The Tunnel," although originally this was an open promenade along the entire length of the Western Wall of the Temple Mount.  Great pains were taken to maintain the structural integrity of the buildings above, while revealing the full length of the Western Wall.

 
As we walk through, we note some fascinating details of the Western Wall stones.

These stones were perfectly preserved by remaining underground for thousands of years.  Note how we can clearly see the small offset of each row.  Every stone is slightly set back from the stone below it.  This gives the viewer the illusion of a perfectly straight wall.  If the stones were exactly aligned, the wall would appear to be leaning forward.

At some point, a plaster covering was placed over the Herodian stones. A fish-tail pattern was stamped into the plaster, and one can even see signs of ancient graffitti.

We continue on, amazed at the scope and length of this engineering feat. At the end, suddenly, the passageway widens and we see a curious, half-rounded polished stone on our left.