The price of oil refers to the spot price per barrel (42 gallons) of benchmark crudes like West Texas Intermediate (WTI) and Brent Crude, driven primarily by global supply and demand, though the OPEC cartel can influence it. Historically, oil was preceded by expensive whale oil, but petroleum rapidly replaced it in the 1850s; global crude prices remained relatively stable until the 1970s, when major shocks occurred. Notable price swings include the 1973 OPEC embargo, the 1979 Iranian Revolution, the 2008 financial crisis, and the 2014–2016 oil glut, which saw a 70% decline—one of the largest since World War II. More recently, the 2020 Russia–Saudi Arabia price war caused a 65% drop during the COVID-19 pandemic, followed by a demand-driven rebound and record-high energy prices by December 2021. In March 2026, the outbreak of the Iran war pushed Brent above $100 per barrel, spiking to $119.50 after strikes near Tehran and the closure of the Strait of Hormuz, though prices moderated after G7 reserve releases. As of June 2026, the ongoing Hormuz conflict keeps markets unstable, with refined prices 35–70% higher and the International Energy Agency warning of a worsening crunch.