There are many ways that Hiroshima and Nagasaki seek to encourage people to think and reflect on the A-bombing of their cities and positive ways to think and work for peace now and in the future. One such way is the provision of seeds by Mayors for Peace.

The seeds derive from ginkgo and other trees that were damaged in the atomic bomb attack on Hiroshima in 1945, which grew again the following spring. These trees have become powerful symbols of peace and regeneration after disaster.

The Mayors for Peace Secretariat distributes gingko and other tree seeds from A-bomb survivor trees to members across the world. Many European members of Mayors for Peace have such ginkgo trees, which they have nurtured and grown from seeds. The seeds and the trees have often been promoted as peace education programmes including art and poetry from schools and are often planted in places of real importance to the Mayors for Peace members.