The St. Peter's Cross, also known as the inverted or upside-down cross, is a symbol associated with Christianity and specifically with Saint Peter, one of the twelve apostles of Jesus Christ. It represents his martyrdom and humility, as he requested to be crucified upside down, considering himself unworthy to die in the same manner as Jesus. The symbol is often used to honor Saint Peter and can be seen in religious art, jewelry, and other Christian representations.