
The prison was an unfinished warehouse intended for cotton and housed hundreds of Union prisoners during the War Between the States. Among vermin and other unpleasantries, they also endured a flood.
Finally, in March 1865, many were freed through a prisoner exchange, and they boarded steamboats headed north toward home. But on April 27, almost 700 of these former prisoners perished in the Mississippi River near Memphis when a boiler exploded on the steamship Sultana. That explosion remains the worst domestic maritime disaster in U.S. history.