Cize–Bolozon viaduct

In 1875, an original span built in the same location but was destroyed later in World War II. The viaduct was reconstructed as an urgent post-war project due to its position on a main line to Paris. It reopened in May 1950.

It has two different levels: the upper level is a railway while the lower carries road traffic. The railway was closed for reinforcement and restoration in 2005, and reopened in December 2010 as part of the Ligne du Haut-Bugey. The lower level is a local road from Poncin to Thoirette.