A symbol that is widely recognized as standing for peace is a dove.
Explanation:
The association dove/peace probably originates from the alliance described in the Old Testament.
After flooding the Earth to purify it, God made an alliance with Noah and his descendants, and promised to never flood the Earth again. When a dove returned to Noah's Ark holding an olive branch, Noah then knew it was safe to leave the Ark with his family and the animals they had saved.
