 The Malmsbury Viaduct is a large masonry arch rail bridge constructed over the Coliban River in 1859 and is classified "A" by the National Trust.The town's school uses the viaduct as its emblem.A stretch of the Calder Freeway (M79) bypassing Malmsbury was officially opened on 12 April 2008, and the removal of heavy through traffic was celebrated eight days later by the holding of a "Monster Street Party" in the town.