Of all the precious metals, gold is the most popular of all the metals as an investment. Gold has been used throughout history as money and has been a relative standard for currency equivalents, until recent times. After World War II, the Bretton Woods system pegged the United States dollar to gold at a rate of US$35 per troy ounce. The system existed until the 1971 Nixon Shock, when the US unilaterally suspended the direct convertibility of the United States dollar to gold and made the transition to a fiat currency system. Since then the price of gold has seen some dramatic rises and has become one of the most popular metals to trade as it has the most effective safe haven and hedging properties.