The World Traveler Challenge is to reward those that go all out and geocache around the world. This cache is for those that have found at least one cache in 4 different countries. Yes, the US does count as one of those countries.
To claim the find you must sign the cache log and post a screenshot of your stats page that shows you have found a cache in at least 4 countries. Finds that don't include a picture will be deleted. If you have trouble with a screenshot, let me know and I will help you. If you are not a premium member, you should be if you have worked hard enough to find caches in four countries. However, if you are not you can post the GC numbers, cache names, countries they are in and the dates you found them.