On the one hand, it’s incredibly simple.

A web page embeds a Google maps street view URL. You click a door that says “Take me somewhere else.” And Google Maps Street View shows you another place on the planet.

On the other hand, it’s simply incredible.

A company — and thousands of volunteers – has built a repository of millions of images, updated frequently, of cities and streets, and mountains all over the world. Not to mention places like Australia’s Great Barrier Reef and Hawaii’s Hanauma Bay, plus portions of the Amazon rainforest. And with a click of a button you can see the south pole, or China’s Great Wall, or the Ginza district of Tokyo … or the surface of another planet.

Try it here:

How does it work?

“It basically works by using an i-frame, which gets dynamically populated with a full-screen Google Maps Street View URL,” Jordan Peck, one of the people behind the project told me via email. “The app loads one of 90 locations, randomizing the selection every time the user clicks ‘Take me somewhere else.’ The door design itself, as well as the on hover animations use CSS3.”

Simple. And spectacular.