When we imagine a journey through the center of the earth to the other side, we’re generally forgetting one little feature: gravity. Because of it, the round trip could take just one hour and 24.5 minutes. The hitch is that it could go on forever.
Via Rene’s Apple
THE TEXAS SCRIBBLER 
One heck of a dig for somebody, though.
And much of it would be pretty hot, too. 😉