Asteroid strikes are rare but not impossible. As proven by last week's impact in Nicaragua the Earth can only protect us from so much.
So what would actually happen if even a 'small' asteroid hit your town or city? Well the Washington National Science Foundation has teamed up with NASA to create an interactive Google Earth Application that'll show you exactly what'll happen, from the impact crater to earthquakes.
The generator lets you pick either a random town or city or -- if you're feeling particularly morbid -- you can enter in your own location.
You'll then be able to choose from a small, medium or large and finally pick whether it's an asteroid or a comet.
So what would happen if a giant comet hit the centre of London? Well for starters the impact crater would stretch from Calais to Leicester with London, Cambridge, Oxford and most of the South East completely obliterated. Moving further out those in Wales and Scotland would suffer from a 7.0 earthquake as well as 1st degree burns.
The resulting fireball would stretch as far as Madrid causing clothing to ignite and huge plums of dust and mud to fly into the atmosphere.
NASA classes this as an 'extinction' event. While the damage to the UK and Europe would be devastating it wouldn't wipe out the human race. Instead it'd be the lack of sunlight.