It depends on what mode of transport you use. I read a book by a lady who ran round the world (seriously!) going via Europe, then Asia, then North America and it took her about 5 years. The flight to the other side of the world is usually about 24 hours so I guess it wouldn’t be much more than 36 hours flying. Plus there are of course all the modes in between – car, boat, train, kayak, balloon, sialing boat. In Jules Verne’s book, Phileas Fogg took 80 days – if you wanted to go round the world, how would you do it?