Old Chain of Rocks Bridge

Old Chain of Rocks Bridge. A Route Through History. , Rocky Start , Natural and built features impact the past, present and future of the St. Louis region. During the last Ice age, ice blocked the Mississippi River channel in this area - forcing the river to carve out a new route over bedrock. The chain of rocks that remain in the river today for several miles north of St. Louis are a series of strong stone ledges that have not yet been eroded by the flowing water. These rocks made the river dangerous to navigate by boat during most river stages - and impossible to navigate during low water. To accommodate riverboat traffic, the Army Corps of Engineers built an 8.4 mile long canal to bypass the chain of rocks in 1953. The rocks that you see here just south of this bridge are a low water dam built by the Army Corps of Engineers in 1964 to raise the water level high enough to cover the chain of rocks upstream and keep the river levels high enough at the top of the canal to allow boats to travel through., Bridging the Past and Present, 1894 and 1915 - The two structures that you see in the river that look like ty castles are draw drinking water from the Mississippi River, 1929 - The Chain of Rocks toll bridge - constructed with funding from local entrepreneurs - opens to the public. The one-mile bridge has a 22-degree bend in the middle to prevent boat captains from having to navigate the bridge piers and water intake towers at the same time. Initially, the bridge features an ornate toll booth beneath an amusement park on the Missouri side and a row of 400 elm trees on the Illinois side., 1936 - Route 66 is rerouted over the Chain of Rocks Bridge, and toll profits soar., Early 1940s - The bright red sections of the bridge are painted the dull green that you see today so that the structure is less visible from the air during World War II., 1970 - The Chain of Rocks Bridge closes, shortly after Interstate 270 opens., 1975 - Bridge demolition is planned, but with the low value of scrap steel at the time, tearing down the structure is determined to not be cost effective., 1999 - The Chain of Rocks Bridge reopens to people walking and bicycling., Mississippi Flyway , Since prehistoric times, the Mississippi River has been used to transport people and goods - but did you know that birds use it too? The Mississippi River is the most heavily used migration route for birds in North America. 40% of all migrating birds in North America make the round trip each year along the Mississippi Flyway from their breeding grounds in Canada and the northern United States to their wintering grounds along the Gulf of Mexico and Central and South America. The waterways, wetlands, and woodlands along the Mississippi River are important resting points for these migrating birds.