Facades covered with shells and clams

The construction material found in many buldings of the city, in the walls of some of the facades of the houses, old arches and gates and also in castles like the Santa Catalina castle is called the oyster stone. It is formed by remains of seashells eroded by the sea and compacted in sand.

In any building made of this material it is very easy to find shells and clams embedded in the stone.