The geographical regions are as follows:

REGION 1 -- USA, Canada
REGION 2 -- Japan, Europe, South Africa, Middle East, Greenland
REGION 3 -- S.Korea, Taiwan, Hong Kong, Parts of South East Asia
REGION 4 -- Australia, New Zealand, Latin America (including Mexico)
REGION 5 -- Eastern Europe, Russia, India, Africa
REGION 6 -- China
REGION 7 -- Reserved for Unspecified Special Use
REGION 8 -- Persevered for Cruise Ships, Airlines, etc...
REGION 0 or REGION ALL -- Discs are uncoded and can be played Worldwide, however, PAL discs must be played in a PAL-compatible unit and NTSC discs must be played in an NTSC-compatible unit.

DVDs encoded for regions other than Region 1 cannot be played on a region 1 DVD player, also, players marketed for other regions cannot play region 1-stamped DVDs