Cellular Jail, Andaman and Nicobar

The Cellular Jail, also known as kala Paani (Black Water), was a colonial prison situated in the Andaman and Nicobar Islands, India. The prison was used by the British especially to exile political prisoners to the remote archipelago. Many notable dissidents such as Batukeshwar Dutt and Veer Savarkar, among others, were imprisoned here during the struggle for India's independence. Wikipedia