If you look closely, you can find a little star embedded in the wall of the Mosque-Cathedral in Córdoba. Known to some as the Estrella de los Deseos (Wishing Star), this star exactly is located in a corner of the Cathedral-Mosque, next to Torrijos street. It is actually a type of fossil. People who walk by often touch it and make a wish, just in case it will be fulfilled.
Despite the alleged magical properties that have been attributed to it by the ordinary people, the wishing star is just a common fossil typical of the calcarenite stone used in the façade of the building, which was hidden when the pillar was carved and used to build the wall. As the limestone eroded over time the fossil, which was made of a sturdier material, started to become visible. That must have been a surprise, hence its alleged miraculous power.
The fossil that now can be seen completely is a type of an equinoideo, and the shell of a Clypeaster, a type of marine sea urchin.