Amritsar
In the Jallianwala Bagh Massacre of 1919 under British Rule a large number of protestors were shot at and killed by British troops.  The city is also famous for Operation Bluestar, a military operation carried out by India in 1984 that was ordered by the Prime Minister of India of the time, Indira Gandhi.  Many Sikhs were angered, as the holy Golden Temple of the Sikhs was damaged by the Indian Army.