A white dove, an olive branch, a rainbow colored flag, the "V' hand shape and the nuclear disarmament symbol (a circle containing one long and two shorter lines inside) are all recognized as peace signs. The circular peace sign is one of the most commonly known symbols in the world.
Originally designed by the Campaign for Nuclear Disarmament, the circular peace symbol was designed in London and debuted in 1958 on clay badges worn during an anti-nuclear march. It is derived from semaphore signals for the letters "N" and "D" as in "nuclear disarmament". Popularity of the symbol spread internationally during the 1960s. It has never been copyrighted, as the CND feels the symbol should be free for all to use.
The "V for Victory" hand shape is made with the palm out and index and middle fingers extended to form the letter V. The sign was widely used at the end of World War II and later adopted by protesters to the Vietnam war during the 1960s.
While the white dove as a peace sign originated with early Christians and has been used to indicate peace for centuries, it gained new recognition in the 1940s when the World Peace Congress chose a Picasso lithograph of a white dove as its emblem.