The Kingdom of Thailand (Thai: ราชอาณาจักรไทย English: Thailand), referred to as Thailand, is the capital of Bangkok, located in the central and southern part of the Indo-China Peninsula, with the Pacific Gulf of Thailand in the southeast and the Andaman Sea in the Indian Ocean in the southwest. It is bordered by Myanmar to the west and northwest, Laos to the northeast, Cambodia to the east, and Malaysia to the south. It has a tropical monsoon climate, the terrain is high in the north and low in the south, and it slopes from northwest to southeast, with a total area of 513,000 square kilometers and a coastline of 2,705 kilometers. As of the end of 2020, Thailand's total population was 65.228 million. Thailand has over 700 years of history and culture. In 1238 AD, Thailand formed a relatively unified country, and successively experienced the Sukhothai Dynasty, the Ayutthaya Dynasty, the Thonburi Dynasty and the Bangkok Dynasty, formerly known as Siam. In the 16th century, colonialists such as Portugal, the Netherlands, Britain and France invaded successively. In 1896, Britain and France signed a treaty that stipulated Siam as a buffer country between British Burma and French Indochina, making Siam the only country in Southeast Asia that was not colonized. At the end of the 19th century, King Rama IV began to open to the outside world, and King Rama V learned from Western experience to carry out social reforms. In June 1932, the Democratic Party staged a coup, changing the absolute monarchy to a constitutional monarchy. In 1949, it was officially named Thailand. Thailand is a member and founding member of the Association of Southeast Asian Nations, as well as a member of the Asia-Pacific Economic Cooperation and the World Trade Organization. It is one of the happiest economies in the world. Thailand is one of the emerging industrial countries and market economies. It implements liberal economic policies and is an export-oriented economy. Gross domestic product in 2021 is $505.6 billion.