Every evening since 1959, Indian and Pakistani troops have lowered their flags together at the Wagah border crossing
When Britain granted India independence, 75 years ago, the territory it had ruled over was divided, or partitioned, into India and the new state of Pakistan (with East Pakistan later becoming Bangladesh).
This created an upsurge of violence, in which approximately 15 million people were displaced and an estimated one million died.
India and Pakistan have remained rivals ever since.
Why was British India partitioned?
In 1946, Britain announced it would grant India independence.
No longer able to afford to administer the country, it wanted to leave as quickly as possible.
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The last viceroy, Lord Mountbatten, set the date as 15 August 1947.
The population was about 25% Muslim, with the rest mostly Hindu but also Sikh, Buddhist and other religions.
Leading independence campaigners Jawaharlal Nehru and Mohandas Gandhi wanted an India that embraced all faiths
"The British used religion as a way of dividing people in India into categories," Prof Navtej Purewal, Indian fellow for the Arts and Humanities Research Council, says.
"For example, they created separate Muslim and Hindu lists of voters for local elections.
"There were seats reserved for Muslim politicians and seats reserved for Hindus.
"Religion became a factor in politics."
Dr Gareth Price, at the UK-based Chatham House foreign-policy institute, says: "When it looked likely that India would get independence, many Muslim Indians became worried about living in a country ruled by a Hindu majority.
"They thought they would be overwhelmed.
"They started to support political leaders who campaigned for a separate Muslim homeland."
Congress Party independence-movement leaders Mohandas Gandhi and Jawaharlal Nehru wanted a united India that embraced all faiths.