It seems near impossible to obtain a visa to North Korea or Iraq by applying in the U.S., but entering through a neighboring nation or setting up a guided tour will usually do the trick.
Most countries have a set of organized visa requirements to facilitate the entry of citizens of other countries for tourism, business, study, work, or retirement purposes. In countries where organized visa requirements are not the rule, getting a visa can confuse and frustrate even the well-seasoned traveler.
Below is a list of the top 10 countries with the most difficult visa processes (in order of increasing difficulty). I have included information on how to go about getting the visa and what you can expect after applying.