Dwarves from the City of Or have been working on creating a safe passage through the Mountains of Triz for many years. The tunnel is supposed to create a safer alternative to the common mountain pass that's currently used for trade routes.
Currently, the tunnels are about halfway done. For the past four years many workers have decided to quit their jobs working on the tunnels. When pressed, they refuse to explain why. This has severly slowed down the work on the tunnels and the Passage of Or is often used as a synonym for work that will never be finished:
Looks like Philip is working on the Passage of Or.