How does a knife become a stadium?

At first thought, weaponry seems like a bad addition to the Olympics (unless we're talking marksmanship, archery or, if you want to go ancient, javelin and shot-put). However, there's a role for weapons in the Olympics that doesn't culminate in competition or a swift arrest -- it just involves a quick, compulsory melting.

London's Metropolitan Police force recently announced that 58 tons of confiscated guns and knives -- plus some keys thrown in for good measure -- will be recycled into girders for the 2012 Olympic Games site in Stratford, East London.

The weaponry-turned-stadium is only one part of the Metropolitan's larger recycling efforts, according to the BBC. The force's 3.3 million spent bullets and casings collected from its firing range are turned into jewelry or picture frames. Used police clothing and worn-out Kevlar body armor somehow become cars. And 20,000 liters of canteen cooking oil live a second life as biodiesel. Police horses even do their part in the recycling efforts, with about 4,000 tons of their manure becoming fertilizer.

The Metropolitan's weaponry upcycling isn't the norm, however. According to FastCompany, the Transportation Security Administration (TSA) sells all of its confiscated guns and knives back to the public -- something the magazine supposes will only lead to more confiscation. But while my imagined government-sponsored gun and knife auction is a somewhat scary sight compared to soaring Olympic girders, I suppose the TSA is being more orthodox in the order of its three R's (reuse does come before recycle).