The glass bridges are a notable feature of Nilt. They are unsupported bridges spanning across the Ribbon that are around five metres wide and appear to be made of a glass-like substance, although they must be far stronger than glass to support their own weight. The exact material is unknown, as are the construction methods used to erect these structures. Underneath the bridges are a series of broad "glass" tubes. These structures have spanned the trenches since before humans first settled on Nilt. They are thousands of years old and their creators are a mystery.
Therrod has a glass bridge equatorwards of the town, although it is not particularly well-maintained and is closed to visitors without permits. Breq travels across the bridge after Seivarden sells her flier, but her journey is cut short when Seivarden, following her, falls from the bridge, and Breq jumps off to save her, falling into one of the glass tubes and using her armor to disperse the energy of the fall.