>If one were to attempt to "walk across the world", this would be about as close as they could get. :)

I know this sounds ridiculous, but I've sometimes fantasized about walking around the world and the best you could do in theory is about 10x the distance from New York to California: South America to West Africa (assuming you can cross a frozen Bering Strait). That's 20,000 miles. In reality, you'd probably face insurmountable political and legal difficulties with crossing borders.

http://en.wikipedia.org/wiki/Circumnavigation#Human-powered

The 9,000 miles Michael Lee Johnson is attempting is pretty impressive. I've got a lot of respect for this guy for trying.

>I'm too tired to check, but Internet, is there any continuos stretch of land that connects one point on earth to it's polar opposite on the sphere?

Yes! I believe so, based on what I said previously. Here are some tools to get you started:

http://www.findlatitudeandlongitude.com/antipode-map/

http://www.daftlogic.com/projects-google-maps-distance-calcu...