Some are calling for a return to the gold standard following the explosion of government debt in Europe and the U.S.
Before 1944, the standard meant governments linked their currencies to gold at a fixed rate. Since then, currencies have been linked to the dollar, meaning money has no underlying asset to back its value, with most currencies trading freely on the foreign exchange markets.
Declining confidence in the dollar and questions about its viability as the world's reserve currency have also made the gold standard appealing.
Proponents of such a standard argue that it would bring back fiscal stability. With a fixed money supply, they say, inflationary pressures would be largely contained and large increases in government budget deficits and public debt a thing of the past.
Skeptics say getting the world to sign on to gold, or any other type of metal, is too big a hurdle and worry about unintended consequences.
For instance, if the U.S. goes to a metal reserve on its own, whatever the metal, others might buy up the metal market, cause enormous appreciation of the dollar, and therefore threaten American exports.