The axis of this peace arch structure lines up exactly with the dome. Bisecting the two is a flame that burns continuously as a symbol of the hope for peace.

The inscription on the plaque translates as:

"Let all the souls here rest in peace; For the evil shall not be repeated".

It's worth pointing out that the Japanese version of this text omits who it is who will not repeat the evil. The Japanese Language is very good at being ambiguous when it wants to be.