Shortly after President Grant left office, he went on a round-the-world journey, with stops all over Europe, in Russia, through the Suez Canal, to China and Japan, arriving in San Francisco and then crossing the North American continent.
I believe he was the first US President (or former President) to do so. Please correct me if I am wrong.
I am guessing such journeys have become more common as travels have gotten easier and cheaper (Grant spent something like $25,000 for his journey).
Which other Presidents have made a round-the-world journey as a single trip?
My information about President Grant is from Jean Edward Smith's wonderful Grant.