In spring of 2011, the Mississippi River swelled to historic levels on the Missouri-Illinois border. The pressure on levees made water from subterranean tributaries boil out of the ground, creating gaping sinkholes in various parts of Cairo, Illinois. While the residents evacuated, the Army Corps of Engineers and the National Guard worked to control the flood with pumps and sandbags. As the waters continued to rise, the choice became clear: the Corps needed to blow a hole in the levee, flood neighboring farmlands and redirect the water. This destroyed the livelihood of many farmers, but saved the town of Cairo.