It looks like something from a movie, but this volcano actually exists in East Java, Indonesia. 

During the day, the volcano has a turquoise-colored acid crater lake at its base which is the site of a labor-intensive sulfur mining operation, in which sulfur-laden baskets are carried by hand from the crater floor.

The lake is recognised as the largest highly acidic crater lake in the world.

But what happens at night is even more amazing. Glowing blue lava can be seen flowing down the volcano and the smoke and steam rising from the blue flames add to the eerie beauty of it all.

Two French nature photographers are making a new documentary about the phenomenon called Kawah Ijen: the mystery of blue flames.