Bayou des Glaises is a particularly slow bayou whose French name likely refers to the loamy, clay soil settlers found along its banks. Beginning at Lake Pearl, it flows about 60 miles northeast and then turns south in a big bend to the Atchafalaya River at Simmesport. Part of an extensive network of sluggish waterways that once connected to the Red River and flowed toward the Atchafalaya River Basin, it is also an ancient Mississippi River path that became essential for travel and commerce in the area. During spring floods, it carried nourishing sediment that replenished the alluvial soils along its banks, and many planters built homes facing the bayou and farmed the fertile land behind them. Residents often crossed by low bridges built for normal and low water stages, though high water flooded those bridges and allowed steamboats to pass over. The Sarto Old Iron Bridge, spanning Bayou des Glaises, was completed in 1916 as a steel truss swing bridge for vehicular and boat traffic, opening on a central pin for larger boats, and several railroad companies also used it while traveling east to the Red River, which then had no bridge. A community called Naples developed where trains were loaded onto barges and boats pushed steamers through Old River, the Atchafalaya, and the Mississippi, becoming a significant railroad terminal before being washed away in the Mississippi River Flood of 1927. The Sarto Bridge also became an important evacuation route for Big Bend residents during frequent high water and flooding, including in 1927; after that flood, the Mississippi's levees were raised and local flood danger was reduced. Now accessible only to pedestrians, the Sarto Bridge is a rare surviving example of its type and was the first bridge in Louisiana placed on the National Register of Historic Places. Across LA Hwy. 451 from the bridge, the Adam Ponthieu Grocery Store and Big Bend Post Office Museum preserves the memory of a post office that served locals from 1847 to 1994; the grocery store was destroyed in 1927 and rebuilt shortly afterward.