The World Passport issuers, have claimed successful entry into several countries with it. There is no independent verification about this one way or the other. Again, you have to get into a discussion over what makes a nation. The many micro-nations, from the absurd to the rather well thought out and planned ones, might be more willing to accept this document as opposed to a major country. And I have heard through reliable second-hand sources of several cases in which it was somewhat documented that the World Passport did allow for entry into some smaller Central and South American countries. There is also the possibility that since it resembles the physical appearance of most passports, immigration officials, maybe in times of peak travel, accepted the passport without proper inspection of it, and honestly erred in allowing the person into the country. These scenarios however would not make me feel very comfortable that I would want to travel internationally with that being my sole piece of documentation. However if you were trying to cross a land border, where some are so porous you just simply walk across the boundary, through an immigration checkpoint and you were doing it more out of curiosity than really needing to get across the border into that new country, it might be worth a try. Worst case scenario, they refuse you and you stay in your home country or whatever country you were authorized to be in.