Nearly 40,000 anti-war activists held a rally at the historic Central Park in New York demanding the elimination of nuclear weapons.
The activists marched past the United Nations headquarters chanting slogans 'No war, no nukes'.
The protest was carried out ahead of Monday's opening of a month-long conference of parties to the Nuclear Non-proliferation Treaty.
The conference, held every five years, will review the treaty.
Led by Hiroshima Mayor Tadatoshi Akiba, the activists on Sunday demanded that the UN and diplomats reviewing NPT ensure that the sufferings of Hiroshima and Nagasaki are not repeated again.
These are the only two cities that suffered atomic bomb attacks towards the end of World War II.
Akiba called on the nations to work together to ensure that the 'world family' does not suffer the pain and go through what his city had gone through in 1945.