Nagasaki City Shiroyama Elementary School, perched atop a hill, is approached from two hills or a stair. The one of the two hills that faces east is called Nagai Zaka ("Nagai Hill") after Dr. Takashi Nagai, the donator of cherry trees planted along the road and the author of a collection of essays called The Bells of Nagasaki, which became the motif for a popular song of the same title composed by Yuji Koseki with lyrics by Hachiro Sato. The other hill is known as Heiwa Zaka ("Peace Hill").

This camphor tree standing at the foot of Heiwa Saka was one large tree before the atomic bombing.
However, it was split and burnt by the atomic bomb, after which fresh buds appeared from the burnt ruins of the tree and two trees now known as "the twin camphor trees" grew up together.

All the children from the first grade to the sixth grade at Shiroyama Elementary School independently learn, feel and conduct heritage activities regarding the bombed school remains and peace monument located at their school. The comprehensive final polishing of these activities is the "peace navigation" studies. In these studies the sixth graders guide children who visit Shiroyama Elementary from other schools around the buildings, deepening their peace education.

Through the word of the children, the prickly ash and the twin camphor trees, along with the remains of the bombed former school building that stand in the school grounds spread out a message not only about the damage of the atomic bomb but also aimed at the future.