The Black Hole of Calcutta, Fort William, Calcutta, India. A small prison where troops of Siraj ud-Daulah, the Nawab of Bengal, held British prisoners of war after the Bengali army captured the fort on 20 June 1756. Too many soldiers were confined in conditions so cramped that many of them died from suffocation and heat exhaustion. From Hutchinson's History of the Nations, published 1915.