Doctor Who
Battle in Tunnel
Donna, Martha, and the Doctor arrive in the war zone where Jenny is created in episode 4x06 “The Doctor's Daughter”.
Source: The Doctor Who Locations Guide
Zygon Tunnel
Clara finds her way down into the Zygon tunnels beneath her flat in episode 9x07 “The Zygon Invasion”. Zygon!Clara returns down into the tunnels in episode 9x08 “The Zygon Inversion”.
Orphan 55 Service Tunnel
The survivors climb down into a service tunnel to travel back to the spa and the Doctor realizes something about the world they are on in episode 12x03 “Orphan 55”.
Source: Cultbox