This song was written in the 1930s by blues musicians Walter Vinson and Lonnie Chatmon but has since become a part of the traditional and standard bluegrass repertoire. You'll hear it at jam sessions all over the world.
There's a bit of bluesy flair in this version of Sitting On Top of the World. It's not too difficult but is really solid and true to the melody.
Here's a complex arrangement with a whole bunch of chromaticism and string hopping thrown in. It'll blow your friends a way, that's for sure!