Although oil is thought to have been first discovered 3000 years ago in what is today's Iran, it was only with the birth and rise of the internal combustion engine in the 1800s and 1900s respectively that the commodity took on a strategic importance, so much so that the combustible liquefied organic substance became known as 'black gold'.
So vital is this fossilised material to modern living - whether for transportation, heating, energy generation or synthetic materials - that global and regional powers have fought wars over the commodity, with much of the unrest in the Middle East being traced back, whether directly or not, to oil's strategic importance.
The Organization of the Petroleum Exporting Countries (OPEC) members and those oil-producing countries outside the cartel are currently at loggerheads over supply and demand, and the barrel price has consequently plummeted over the past three years - providing welcome relief for motorists at the pumps, but causing major upset in boardrooms of oil producers across the world.