The city was established in the 17th century by the British, who developed it into a major urban centre and naval base. By the 20th century, it had become an important administrative centre, as the capital of the Madras Presidency.
Tholkappia Poonga or Adyar Eco Park (also known as Adyar Poonga) is an ecological park set up by the Government of Tamil Nadu in the Adyar estuary area of Chennai, India. It was created to restore the vegetation of the freshwater eco-systems of the Coromandel Coast, especially the fragile eco-system of the Adyar estuary and creek. Created at a cost of around ₹ 1,000 million, it covers 358 acres (1.45 square kilometres) of land. The park's ecosystem consists of tropical dense evergreen forest, predominantly comprising trees and shrubs that have thick dark green foliage throughout the year, with over 160 woody species, and comprises six vegetative elements such as trees, shrubs, lianas, epiphytes, herbs and tuberous species. About 65 percent of the poonga is covered by water and artefacts and signages.