Nasa estimates that if Apophis were to hit Earth, it would explode with as much energy as 400 megatonnes of TNT.

BBC: Foresight mission spacecraft Image

It is American economy that would explode, probably taking what's left of the world economy with it.

BBC: America's fiscal suicide pact

This would mean it could explode and fragment in the atmosphere with only the shock wave reaching the ground.

BBC: Mystery space blast 'solved'

If Cyprus had gone for help when investors still thought the single currency was about to explode, it would have had a stronger hand.

BBC: Lessons of Cyprus