Oil is the lifeblood of every country. We use it for transportation, logistics, manufacturing and more. Thick black oil is pulled from the earth via an extraction process before being refined in large facilities to make it usable in, for example, cars and trucks. The Middle East (Saudi Arabia, Iraq, Iran, etc.), Russia and the United States are the biggest producers of oil. As you can imagine, oil is a hot topic for political leaders because its supply and demand can have a significant impact on the peace and prosperity of their countries. Australian investors could track the price of oil using an ASX oil ETF.