English: The Chain of Rocks Canal and Chain of Rocks Lock, also known as Lock number 27, on the Mississippi River near St. Louis, Missouri, USA. The canal and locks are physically situated within the state of Illinois near the towns of Granite City and Madison. The U.S. Army Corps of Engineers constructed the canal to bypass a rocky stretch of the Mississippi River known as the Chain of Rocks. These locks are the last locks heading down the Mississippi and are the only locks on the Mississippi River south of the confluence with the Missouri River. The towns in the far distance in the picture are Hartford, Wood River, and East Alton, Illinois