Arched Tunnel
The Steward's Fear Nightmare #8 (x2)
Location
4 (3)

Underworld 1.

Travel: Reveal all facedown cards underneath Arched Tunnel, one at a time. Then, place the top card of the underworld deck facedown underneath Arched Tunnel, if able.

And each time that it passed the line of the Great Gate it went through an arched tunnel... –The Return of the King