The Cellular Jail is Port Blair's essential sight and one of the most powerful colonial-era memorials in India. Built by the British after the 1857 uprising, it held political prisoners far from the mainland in small individual cells. The brick corridors, central tower, gallows, and museum displays make clear how deliberate that isolation was.
Allow enough time to walk through the surviving wings before the evening light-and-sound show. The show is well known, but the building itself is the stronger experience.