The U.S. dollar is the currency most used in international transactions. Several countries use the U.S. dollar as their official currency, and many others allow it to be used in a de facto capacity. It's known locally as a buck or greenback.
Hong Kong was a dependent territory of the United Kingdom from 1842 until the transfer of its sovereignty to the People's Republic of China in 1997. Even so, Hong Kong maintains its own monetary system.
