A rally that kicked off in June has boosted oil prices to the highest closing levels in more than three years.

The oil price downturn is now 3½ years old, but it didn’t gather devastating momentum until OPEC’s fateful Thanksgiving day meeting in 2014.

During that meeting, Saudi Arabia, OPEC’s biggest producer and the world’s top exporter, refuse to cut production to kill a global oil glut and stop a five-month slide in prices. Crude futures, which were down about 30 percent from their June highs at that point, collapsed 10 percent in the next session and eventually plunged to 12-year lows.

The Saudis strategy of letting the oil market balance itself failed as U.S. producers learned to pump at lower prices. OPEC eventually conceded and agreed in November 2016 to curb output.

Now, oil prices are at the highest closing levels since December 2014 and within close range of prices last seen on Nov. 28, 2014, the day after OPEC’s decision.