Guided tours of the Western Wall tunnels offer an entirely different perspective on Herod's epic construction: visitors are led along a 488m passage following the northern extension of the Wall. The excavated tunnel burrows down to the original street level, allowing visitors to tread the same ground as the ancients. Guides give fascinating insights into how these mighty walls were erected – Herod's stonemasons chiselled blocks up to 14m long and weighing almost 600 tons apiece.
You can only visit the tunnels on guided tours (Hebrew and English multiple times a day; French, Spanish and Russian less regularly in summer only), which take about 75 minutes and must be booked in advance. These tours are very popular and fill up fast – try to book at least a week ahead.