You have probably heard of 'red hot' but never 'blue hot' and thats exactly what this volcano is. Indonesia's Kawah Ijen Volcano gives off a blue hue which gives it an other worldly look at night. The mountain contains a large amount of pure sulfur which gives off the incredible 'neon blue' colour as it burns.
Of course getting these pictures is a challenge in its self, with the slopes reaching a scorching 239 degrees fahrenheit. These amazing photographs were taken by Olivier Grunewald.