Askja is a volcanic caldera located in the central highlands of Iceland. It was formed during a massive eruption in 1875, which significantly altered the landscape. The caldera is about 50 kilometers in diameter and contains a crater lake called Öskjuvatn, known for its striking blue color. The area around Askja is characterized by rugged terrain, geothermal activity, and unique geological features. It is part of the larger Vatnajökull National Park and attracts hikers and nature enthusiasts. The region is also significant for its role in scientific research related to volcanology and geology.