Kawah Ijen

Kawah Ijen is a volcanic crater lake located in the Ijen volcano complex in East Java, Indonesia. It is known for its acidic crater lake, labor-intensive sulfur mining, and the phenomenon of blue fire, which is ignited sulfuric gas that emerges from cracks at temperatures up to 600 °C. The lake is recognized as the largest highly acidic crater lake in the world and has a pH of <0.3. The crater is also home to a labor-intensive sulfur mining operation, where miners carry sulfur-laden baskets by hand from the crater floor. The area is also known for its stunning natural beauty, with a turquoise-colored lake and surrounding landscape of volcanic rocks and forests