Eldgjá, also known as "fire canyon," is a volcano and canyon in Iceland that experienced a major eruption around 939 CE. This eruption was the largest effusive eruption in recent history, covering about 780 square kilometers of land with 18.6 cubic kilometers of lava from two major lava flows. The Eldgjá fissure is part of the Katla volcano and is the longest volcanic fissure in Iceland. The eruption had widespread impacts on the Northern Hemisphere climate, leading to noticeable cooling and cold winters across Eurasia. Today, Eldgjá is a popular tourist attraction with its stunning landscapes and unique geological features.