Bhutan is a landlocked nation in the Eastern Himalayas, officially recognized as the Kingdom of Bhutan. It is bordered on the north by China and on the south by India. Although Nepal and Bangladesh are close to Bhutan, they do not share a land boundary. The nation has a population of over 754,000 people and a land area of 38,394 square kilometers, ranking 133rd in the world. Bhutan is a secular monarchy that practices Vajrayana Buddhism. The country's green subtropical plains in the south rise from the subalpine Himalayan mountains in the north. There are peaks in Bhutan's Himalayas that are more than 7,000 meters above sea level. Bhutan's highest peak, Gangkhar Puensum, may also be the world's highest unclimbed mountain. Bhutan's biodiversity, which includes the Himalayan takin, is known for its diversity. Bhutan's capital, Thimphu, is the country's largest city. Bhutan and neighboring Tibet witnessed the spread of Buddhism, which began in the Indian subcontinent during Gautama Buddha's lifetime. From the southern Pala Empire of Bengal, the Vajrayana school of Buddhism spread to Bhutan in the first millennium. During the collapse of Buddhism in India, Tibet, Bhutan, Sikkim, and parts of Nepal became the last strongholds of the Mahayana schools. Bhutan was influenced by the Tibetan Empire as well. Ngawang Namgyal united Bhutan's valleys into a single state in the 16th century. Three Tibetan invasions were defeated by Namgyal, who also subjugated rival religious schools, codified the Tsa Yig legal system, and founded a theocratic and civil administration. Namgyal was the first Zhabdrung Rinpoche, and his successors, including the Dalai Lama in Tibet, served as spiritual leaders of Bhutan. Bhutan ruled over vast swaths of northeast India, Sikkim, and Nepal in the 17th century, and had a strong presence in Cooch Behar State. During the Bhutan War in the 19th century, Bhutan gave the Bengal Duars to British India. The House of Wangchuck ascended to the throne and sought stronger relations with the British in India. A treaty signed in 1910 promised British foreign policy advice in return for Bhutan's internal autonomy. In 1949, a new treaty with India was signed, in which both countries acknowledged the sovereignty of the other. Bhutan became a member of the United Nations in 1971. Bangladesh, Israel, Kuwait, Brazil, Japan, Thailand, and Turkey, as well as the European Union, have all extended their ties since then. Bhutan has its own military forces, despite being dependent on the Indian military. A representative government with an elected National Assembly and a National Council is established by the 2008 Constitution. Bhutan is a member of the South Asian Association for Regional Cooperation since its inception. Bhutan was ranked third in South Asia in the Human Development Index in 2020, behind Sri Lanka and the Maldives.