It is a hauntingly beautiful scene that looks like it has been taken straight from a sci-fi film.
But enchanting footage of the glowing blue lava rippling down the sides of a volcano was in fact shot in Indonesia.
The phenomenon of the Kawah Ijen volcano in East Java is the subject of a new French documentary that examines the rare spectacle.
While the sulphur appears bright red during the day, at night it begins to glow eerie shades of blue.
The smoke and steam rising from the blue flames add to the otherworldliness of the rare volcano.
The colour comes from burning sulphur which pours from the side of the volcano and is collected by miners, according to French magazine Grands Reportages.
Two French nature photographers captured the captivating footage, which was released in a teaser this month for their upcoming documentary Kawah Ijen: the mystery of blue flames.