SuperRare

By day Kawah ljen is a pretty ordinary
volcano. Okay, it's still a massive active
crater that could erupt at any minute, but
still ordinary by volcanic standards.
As night falls the lava river transforms into
an exceptional sci-fi blue hue. The blue
glow isn't actually lava, it's a flame
produced when sulfuric gases from the
volcano come into contact with the
oxygen-rich atmosphere.
If you want to visit Kawah ljen volcano
you'll need a gas mask to protect you
from the toxic sulfur fumes.