Cross of Saint Peter

The cross of Saint Peter is a symbol used in Christianity. It looks like a regular cross, but with the lines flipped upside down, so the longer line is on the bottom and the shorter line is on the top. This is because it's meant to represent the way Saint Peter was supposedly crucified - he asked to be crucified upside down because he didn't feel worthy of being crucified the same way as Jesus.

So basically, the cross of Saint Peter is a special kind of cross that reminds Christians of a story about a really important guy named Saint Peter who died in a special way because he loved Jesus so much.