Until the early astronauts took their first steps into space, mankind wasn't really 100 percent sure that the Earth was round. How were they supposed to know? They didn't have a Porsche Cayman.

This new ad from Porsche features the Cayman driving rapidly along a globe-like surface just like the bonus stages in Sonic 3. (If you're under the age of 25 and have no idea what I'm talking about, Google it.)

I actually think it's pretty cool, and not your traditional Porsche ad, which is full of dramatic music and race tracks and stuff. Any theories as to how it was done are welcome.

Also, there's a bonus here: apparently there's a famous Porsche "relative" of the Cayman somewhere in one of the frames. Can anyone spot it?