In some countries, non-local internal travel may require an internal passport, while international travel typically requires a passport and visa. A trip may also be part of a round-trip, which is a particular type of travel whereby a person moves from one location to another and returns.There are many instances where words that are the same are spelled differently in different countries that use English as a primary language. American spellings of specific words do differ from the commonly acceptable forms in Britain. Traveling and travelling are an example of this phenomenon.