Final answer:
World War II led to many countries abandoning the gold standard during the 20th century, but it was President Nixon's suspension of gold conversion in 1971 that ultimately ended it.
Step-by-step explanation:
The event that brought an end to the gold standard was World War II. However, the final nail in the coffin for the gold standard was when President Nixon responded to an economic crisis by effectively abandoning it in 1971. This decision was due to the pressures of international competition, the rebuilding of postwar economies in Asia and Western Europe, and the fact that foreign dollar holdings exceeded U.S. gold reserves, making it untenable for the US to maintain the gold standard as it was under the Bretton Woods agreement of 1944. After the unilateral suspension of gold conversion and subsequent devaluations of the dollar, the Bretton Woods system came to an end, marking a fundamental shift away from a global economy pegged to gold.