The Far Lands is the area of the map formed at the edge of Minecraft prior to 1.8. Basically, the Minecraft planet creation algorithm breaks down going that far out and some very odd things happen to the terrain. If you traveled on foot to the Far Lands from your spawn point it would be about the same distance as about a third of the circumference of the earth at the equator. Many have made it to the Far Lands with hacks and cheats, but one YouTuber, @kurtjmac is doing it on foot one day at a time.

Not only is he making this journey, but he is recording it every step of the way on his YouTube channel and is now up to episode #318(linked above). Recently his "Far Lands or Bust" project was featured in an article for the New Yorker and I seriously recommend you read it.

"On March 28, 2011, a man who calls himself Kurt J. Mac loaded a new game of Minecraft. As the landscape filled in around his character, Mac surveyed the blocky, pixellated trees, the cloud-draped, mountains, and the waddling sheep. Then he started walking. His goal for the day was simple: to reach the end of the universe.

Nearly three years later, Mac, who is now thirty-one, is still walking. He has trekked more than seven hundred virtual kilometres in a hundred and eighty hours. At his current pace, Mac will not reach the edge of the world, which is now nearly twelve thousand kilometres away, for another twenty-two years."

http://farlandsorbust.com/

http://www.newyorker.com/online/blogs/elements/2014/01/a-journey-to-the-end-of-the-world-of-minecraft.html