Thailand (/ˈtaɪlænd/ TY-land or /ˈtaɪlənd/ TY-lənd; Thai: ประเทศไทย, rtgs: Prathet Thai, pronounced [pra.tʰêːt tʰaj] ), officially the Kingdom of Thailand (Thai: ราชอาณาจักรไทย, rtgs: Ratcha-anachak Thai [râːt.t͡ɕʰa.ʔaː.naː.t͡ɕàk tʰaj] ), formerly known as Siam (Thai: สยาม, rtgs: Sayam [sa.jǎːm]), is a country at the centre of the Indochinese peninsula in Southeast Asia. With a total area of approximately 513,000 km2 (198,000 sq mi), Thailand is the world’s 50th-largest country. It is the 20th-most-populous country in the world, with around 66 million people. The capital and largest city is Bangkok.