The 2011 eruption of Grímsvötn was a Plinian eruption of Grímsvötn, Iceland's most active volcano, which caused disruption to air travel in Northwestern Europe from 22-25 May 2011. The last eruption of Grímsvötn was in 2004, with the previous most powerful eruptions in 1783, 1873 and 1902. The Grímsvötn eruption was the largest eruption in Iceland for 50 years.