The following outline is provided as an overview of and topical guide to Sri Lanka: Sri Lanka – island country in the northern Indian Ocean off the southeast coast of the Indian subcontinent in South Asia. Known until 1972 as Ceylon (/sɨˈlɒnˌ seɪ-ˌ siː-/), Sri Lanka has maritime borders with India to the northwest and the Maldives to the southwest. Sri Lanka has a documented history that spans over 3,000 years, but there are theories to suggest that Sri Lanka had pre-historic human settlements dating back to at least 125,000 years. Its geographic location and deep harbours made it of great strategic importance from the time of the ancient Silk Road through to World War II. Sri Lanka is a republic and a unitary state governed by a presidential system. The capital, Sri Jayawardenepura Kotte, is a suburb of the largest city, Colombo. It is also an important producer of tea, coffee, gemstones, coconuts, rubber, and the native cinnamon, the island contains tropical forests and diverse landscapes with a high amount of biodiversity.