A modified Google Earth client can enable you to go anywhere in the world. Extending the possibilities, google has embedded journey on Moon and Mars with it.
“It felt more like a ride than a computer program, something between an observation-deck and a glass-walled spaceship. As a result of this totally seamless, immersive experience, we decided to name it the Liquid Galaxy,” Google writes.
Thought the project at this time is just evolving, they are working hard on it to create something more creative and useful for generic people. Watch the video: