Lucknow
The ruins of the British Residency in Lucknow are maintained exactly as they were left after the 1857 Siege — with cannonball-pocked walls, broken pillars, and the graves of those who fell within, all preserved as a national monument. It's a haunting and deeply evocative place to spend a quiet hour.
The small museum within the Residency complex has original weapons, paintings, and accounts of the siege — don't skip it.