Sikkim is a state in northeast India, bordered by Bhutan, Tibet and Nepal. Part of the Himalayas, the area has a dramatic landscape that includes India’s highest mountain, 8,586m Kangchenjunga. Sikkim is also home to glaciers, alpine meadows and thousands of varieties of wildflowers. Steep paths lead to hilltop Buddhist monasteries such as Pemayangtse, which dates to the early 1700s. Sikkim is a landlocked state of India, and the last to give up its monarchy and fully integrate into India in 1975. Located in the Himalayan mountains, the state is bordered by Nepal to the west, China's Tibet Autonomous Region to the north and northeast, and Bhutan to the east and the Indian state of West Bengal to the south. With 607,688 inhabitants as of the 2011 census, Sikkim is the least populous state in India and the second-smallest state after Goa in total area, covering approximately 7,096 km2 (2,740 sq mi). Sikkim is nonetheless geographically diverse due to its location in the Himalayas; the climate ranges from subtropical to high alpine, and Kangchenjunga, the world's third-highest peak, is located on Sikkim's border with Nepal. Sikkim is a popular tourist destination, owing to its culture, scenery and biodiversity. It also has the only open land border between India and China. Sikkim's capital and largest city is Gangtok. Almost 25% of the state is covered by the Khangchendzonga National Park. According to legend, the Buddhist guru Padmasambhava visited Sikkim in the 8th century CE, introduced Buddhism and foretold the era of the Sikkimese monarchy. Sikkim's Namgyal dynasty was established in 1642. Over the next 150 years, the kingdom witnessed frequent raids and territorial losses to Nepalese invaders.[10] In the 19th century, it allied itself with British India, eventually becoming a British protectorate. In 1975, a referendum abolished the Sikkimese monarchy, and the territory instead became part of India. Sikkim has 11 official languages: Nepali (which is its lingua franca), Sikkimese, Hindi, Lepcha, Tamang, Limbu, Newari, Rai, Gurung, Magar, Sunwar and English. English is taught in schools and used in government documents. The predominant religions are Hinduism and Vajrayana Buddhism. Sikkim's economy is largely dependent on agriculture and tourism, and as of 2014 the state had the third-smallest GDP among Indian states, although it is also among the fastest-growing. In 2015, Sikkim fully implemented organic farming statewide, becoming India's first "organic state", while in 2016, it restricted the usage of plastic water bottles (in government functions and meetings) and styrofoam products, becoming India's "cleanest state".