OPEC stands for the Organization of the Petroleum Exporting Countries, a cartel of major oil-producing nations.

In 1973, in response to the Yom Kippur War, the Arab members of OPEC decided to use oil as a political weapon.

They imposed an oil embargo on nations that had supported Israel in the war, most notably the United States and the Netherlands.

OPEC also sharply cut production, causing the price of oil on the world market to quadruple.

This led to a major energy crisis in the industrialized world, with long lines at gas stations and government calls for energy conservation.

The oil crisis triggered a period of 'stagflation'—a combination of high inflation and economic recession—in many Western countries.

The crisis demonstrated a major shift in global economic power from the industrialized nations to the oil-producing states.

In the long term, it spurred a drive for greater energy efficiency, the development of alternative energy sources, and the creation of strategic petroleum reserves.

The crisis marked the end of the long post-World War II economic boom.

It highlighted the vulnerability of the global economy to disruptions in the supply of oil.