The Visa Waiver Program (VWP) is a program of the United States Government which allows citizens of specific countries to travel to the United States for tourism, business, or while in transit for up to 90 days without having to obtain a visa. The program applies to the 50 U.S. states as well as the U.S. territories of Puerto Rico and the U.S. Virgin Islands in the Caribbean, with limited application to other U.S. territories. All of the countries selected by the U.S. government to be in the program are high-income economies with a very high Human Development Index and most of them are generally regarded as developed countries.