sentences:  Moreover, in March 1938, CASCO made a big oil discovery in Saudi Arabia booming the oil industry in the country and coincidentally the U.S. became more interested in Saudi oil.As a result, on February 4, 1940, as the World War II was approaching, the U.S. had established a diplomatic presence in Saudi Arabia to have closer relations with the Saudis and to protect it from enemy hand; Bert Fish, former ambassador in Egypt was elected as the U.S. ambassador in Jeddah.The United States dollar is the "de facto" world currency.