The B61 nuclear bomb was originally commissioned to thwart the threat of Soviet encroachment on Europe during the 1960's. Even though the Cold War has been over for decades, the United State's nuclear arsenal remains in operation across the globe.
Thousands of such nuclear weapons have been removed from the region over the years, but several hundred remain, and are costing taxpayers millions to maintain. One B61 costs $28.9 million each, totaling over $11 billion for the arsenal.
Some overseas NATO allies prefer to maintain the stockpiles as a political symbol of US solidarity. Unfortunately for taxpayers, we're the ones footing the bill. NATO allies provide $0 in support to maintain the aging nuclear payloads.
As the New York Times reports, "The Cold War is over and no American military commander can conceive of their ever being used. Even so, President Obama has put $537 million in his 2014 budget to upgrade these bombs."