Crux Immissae: Although the empty cross is known as the Protestant cross, its simplicity makes it popular among Roman Catholics, too, as it seems to be here in the desert outside Albuquerque. These crosses are examples of crux immissae: upright posts crossed by horizontal beams. Wooden crosses were used by the Romans for execution, and it was on Mount Calvary outside the city walls of Jerusalem where Jesus was executed, along with two common criminals. Do you see Mount Calvary below? San Jose Cemetery.