A young American woman holds out a flower to a member of the National Guard in Washington during a march against the Vietnam War in 1967. This image is today embedded in our collective memory. | Photo: Marc Riboud / Magnum Photos / Keystone

Despite the raised, clenched fist being his favourite pose, Nobel Peace Prize laureate Nelson Mandela, the first president of democratic South Africa, has become a symbol of peaceful change, along with Mahatma Gandhi and Martin Luther King. | Photo: Louise Gubb / Keystone

The 1966 Easter March led from Andelfingen to Zurich. Participants were protesting against Switzerland’s intention to add nuclear bombs to its arsenal. The most famous peace sign on these banners was designed by Gerald Holtom in 1958 for the first-ever Easter March from London to Aldermaston, organised by the Direct Action Committee against Nuclear War. | Photo: Fritz Grunder / Photopress-Archive / Keystone

When the Berlin Wall fell on 9 November 1989, the border guards in East Berlin and the crowds of people streaming across the border from both sides remained peaceful – despite initial portents to the contrary. This made the event all the more symbolic. | Photo: Gerard Malie / AFP via Getty Images

The 2023 Ukraine Peace Conference on the Bürgenstock also offered highpoints of symbolism and ambivalence. Was it about more than mere appearances? | Photo: Alessandro della Valle / Keystone, Frank Barratt / Keystone

Yoko Ono and John Lennon protesting against the Vietnam War in 1969. | Photo: Alessandro della Valle / Keystone, Frank Barratt / Keystone