The dollar system, gold and the U.S. empire
The current international monetary system is a system of “fiat currency” centered on the U.S. dollar. It is bound up with the financial, political, and military system unofficially called the U.S. empire. To maintain the empire, the U.S. spends about 10 times more on its annual “defense” budget than any other country. Therefore, when it comes to raw military power, especially firepower and the ability to project it around the globe, the U.S. is a military power second to none. Unlike in the pre-1945 world, no other imperialist power can even think of challenging the U.S. militarily.
The U.S. empire in its modern form — in contrast to the North American U.S. proper and the relatively small but growing colonial empire that the U.S. had been building since the Spanish-American War of 1898 — dates to the lopsided victory of the U.S. over Nazi Germany (1) and Imperial Japan in 1945. Thereafter, and this was confirmed in the Suez Crisis of 1956, [link to posts which discuss this] no other imperialist power can undertake a major military operation without U.S. approval.
This emerging situation enabled the U.S. at the Bretton Woods Conference — held in Bretton Woods, New Hampshire, in 1944 — to establish the U.S. dollar as the world currency and the U.S. Federal Reserve System as the world central bank. The dollar remains the world currency even though the U.S. dollar since 1971 has not been convertible into gold.
Originally, the U.S. built up a huge gold hoard by running balance of trade surpluses that were the result of the superior productivity of its industrial, extractive and agricultural enterprises. The size of the U.S. gold hoard was further increased in the 1930s when with a new European war looming, European capitalists moved much of their gold to the U.S. in exchange for U.S. dollars. Some European governments moved their gold reserves to the U.S. for safekeeping as well.