Thailand is the 20th most populous country in the world, located at the center of Southeast Asia with a land area of 513,120 km2. Thailand is categorized into key areas: the northern region is hilly and mountainous, the northeast region is a high plain, with the central region as a large, low plain, the eastern region has valleys and small hills, with the western region being hilly and mountainous. The southern end of the country is a peninsula with the Andaman Sea to the west and Gulf of Thailand. Located in the tropical region, Thailand’s climate is relatively warm all year round.