Lenticular Cloud over Klyuchevskaya Sopka Mountain, Russia by Denis Budkov. Klyuchevskaya Sopka is a stratovolcano, the highest active volcano of Eurasia. Its steep, symmetrical cone towers about 100 kilometres from the Bering Sea.
The Northern Lights are actually the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun's atmosphere. Variations in colour are due to the type of gas particles that are colliding.