When visiting the cave called Cova de La Garganta, located in a beautiful area of the municipality of Senija, nearby one can find a natural wonder that can rarely be seen with the naked eye: a fossilised tree. Generally, these crystals are formed by precipitation of bicarbonate and carbonate anions, combined with calcium or magnesium cations, by processes linked to the dissolution of the rock (karstification) and subsequent precipitation in tectonic cracks, fissures or cavities (caves).