1. Western Wall Tunnels — Old City, Jewish Quarter
The buried length of the Temple Mount's western wall — the best hour underground in Israel.
The Western Wall Tunnels run north along the hidden length of the Temple Mount's western retaining wall, far beyond the small exposed section at the prayer plaza, through spaces buried under the Muslim Quarter for centuries.
The scale of the Herodian masonry underground is genuinely startling — including one foundation stone weighing several hundred tonnes — and the route passes ancient streets, cisterns and a Hasmonean-era aqueduct.
Entry is by guided tour only, booked in advance, and it sells out. Sections are narrow, which is worth knowing if confined spaces are a problem.
Good to know: Book well ahead — this is the single most oversubscribed tour in Jerusalem.