Cars on Great River Road in Godfrey, Ill., pass the many barges and tugboats backed up on the Mississippi River on Wednesday as crews try to repair the river’s busiest lock. Workers closed Lock 27 on Saturday after discovering that a protection cell had split open and allowed rock to spill into the river, obstructing the passage. Roughly half of the nation’s farm exports pass through the lock near St. Louis. (Telegraph via Associated Press)