The Cellular Jail is the most-visited historic site in the Andamans and one of the most important sites of Indian Independence movement memory. The British built it explicitly as a holding facility for political prisoners — separating them from the mainland by 1,200 km of water made it the ultimate exile, hence the local name 'Kala Pani' ('the Black Waters'), shared with the colonial-era term for transportation overseas.

Construction ran from 1896-1906. The seven-winged radial design (only three wings survive) held 698 single cells, each measuring 4.5 x 2.7 metres, designed for absolute solitary confinement — prisoners could not see or hear each other. Cells were arranged so each wing's cells faced the back of another wing's cells, preventing any visual contact.

Among the prisoners held here were Vinayak Damodar Savarkar (transported in 1911 and held for 10 years), Batukeshwar Dutt (the Bhagat Singh-era revolutionary), and dozens of other freedom fighters. The work regime — extracting coconut oil with hand-presses, breaking stone — was punitive by design. Hunger strikes were brutally suppressed. Three prisoners died in a 1933 strike alone.

The Cellular Jail was declared a National Memorial in 1979 by Prime Minister Morarji Desai. A daily sound-and-light show in the central courtyard narrates the history. MyTripMyTravel includes it on the Port Blair heritage day with a vetted historian guide who can frame the visit beyond the tourist register; the weight of the site rewards contextual reading.