The Sarto Old Iron Bridge, built in 1916, is a steel truss bridge traversing Bayou des Glaises in the rural community of Big Bend. The Sarto Bridge is a pedestrian and vehicular bridge, one lane wide with a three part centered span mounted on a pivoting gear and ratchet mechanism. The bridge is no longer in operation but is an example of one of the few surviving principal bridge types of the early twentieth century.The bridge is divided into three segments, or spans. The central swing span is approached on both sides by a ramp mounted on wooden trestles with steel rackings. This span consists of two modified queen post truss sections, each of which runs from a concrete trestle near the bank of the central pivoting support. The two truss sections, formed by riveted steel lattice work, support the bridge's weight on the closed position. In the open position, the trusses are supported by cables, which run to four central, vertical posts over the pivoting cylinders.During the 1930's, Bayou des Glaises was no longer considered navigable on the horizontal cog, which rotated the bridge, was disconnected. By 1988, the bridge fell into disrepair and was disconnected. On November 21, 1989, the bridge was listed on the National Register of Historic Places. On April 29, 1990, a historic marker was dedicated attesting to the significance
of the old iron bridge.