Ijen Volcano Crater is one of the most attractive and dangerous places in the world. Active volcano, constantly spewing sulfur smoke clubs, the world’s largest acid lake Kawah Ijen, incredible in its beauty blue fire and extremely hard working conditions in the sulfur mine. We went down into the crater to see everything with our own eyes. The Ijen volcanic complex consists of several strato volcanoes and cinder cones and a 20 km wide caldera. Ijen caldera is the largest in Java. The size of the crater is about 960 m x 600 m. The primary dangers at Ijen are pyroclastic flows, lahars, and lava flows But tourists are interested in the acidic crater lake shore which is a natural large deposits of sulfur.