First contact... or the start of World War III?

Not so long ago, an enormous fiery cloud in the skies above Russia could only mean one thing: The beginning of something very very bad indeed. 

At the height of the Cold War, a vision like this would set off screams of terror and mass panic, rather than the soft gasps of wonder and awe-struck conversation...

But it's not the end of the world, nor is it the beginning of a fine friendship with alien neighbours.

For obvious reasons, these rare cloud formations are also known as 'UFO clouds' - because of their spooky resemblance to the space ships we are all expecting to imminently arrive in the skies above us.

Sci-fi films as far back as Close Encounters Of The Third Kind (1977) - and more recently Independence Day (1996) - have depicted aliens camouflaging their craft in boiling cloud formations.

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