To keep things organized and easier to navigate, DVDs are seperated by Region Code. The Region Code of a DVD denotes what type of DVD player can read the disc, for example, a Region 2 DVD can only be played on a Region 2 DVD player (or a Region Free player).
Region 1
United States (Including Puerto Rico), Canada and Bermuda.
Region 2
Europe (except Belarus, Russia, Ukraine and CIS), Greenland, British Overseas Territories, Overseas France, Middle East, Eswatini, Lesotho, South Africa, and Japan
Region 3
Southeast Asia, South Korea, Taiwan, Hong Kong, and Macau
Region 4
Latin America (except French Guiana and Puerto Rico), Caribbean (except French West Indies), and Oceania (except French Polynesia, New Caledonia, Wallis and Futuna, and Hawaii)
(Region Code areas taken from Wikipedia.)