Ummm, easy....

http://en.wikipedia.org/wiki/Evolution

Of course this is far from complete, the moment the process began is still being investigated. But all the hard evidence currently available all points to the fact that the world around us is part of an ongoing process of building blocks in our universe organising, and reorganising themselves. All build on a foundation of gaining better understanding through exploration of every avenue available.

Clearly, we don't yet know what came before the moment we currently call the big bang. But not knowing that doesn't make the belief that a creator must have done it any more valid than it was in fact my cat that did it.

Now if you can provide 10% of the evidence available for my way of thinking I'll be impressed.

Cheers

Cris