Only decommissioned nuclear reactors transformed into amusement parks beats this: a handful of unused grain silos in Iowa, United States have been converted into eight-storey tall ice climbing walls, prompted in part by the immediate region's lack of vertical surfaces.
In the fall of 2001, Don Briggs, Univeristy of Northern Iowa professor and Cedar Falls resident, was helping a friend till his farmland. While driving back and forth across the field, a distant line of silos caught his eye. Being an avid rock and ice climber, Briggs wondered how he could successfully climb the silos. Though his initial idea was to rock climb the infamous stuctures, Briggs ultimately decided to attempt to ice climb them.
Briggs has since fine-tuned a system to "ice" the silos by rigging hoses at the top of the silos, which drip water that eventually freezes, creating a challenging wall of ice that changes constantly, depending on the vagaries of the weather and wind.
In the climbing seasons since then, beginner and expert climbers in this famous farming state have been able to hone their skills closer to home, enjoying these re-adapted agricultural landmarks and a "warming house" on the grounds of the farm. For more information, check out Silo Ice Climbing.