A hidden treasure: the Sima de la Higuera (Pliego, Region of Murcia, Spain)

The “Sima de la Higuera”, named after the fig tree which protects its entrance, is renowned among speleologists and scientists for its magnificent rock formations.

Additionally, it is the largest cave in the region of Murcia, at more than 5,500m in length. But what makes this cave one of the most important hydrothermal caves in Europe is the spectacularity and variety of its speleothems.

Unlike most caves, the origin of Sima de la Higuera is basically hydrogenic, and that poses a question: What does this mean? Simply that in this particular case, the liquid mixture of chemicals and water, which has been sculpting the cave for thousands of years, doesn´t filter away from the surface – albeit it has happened in some periods of its history- but there have predominantly been thermal ascendant currents of water which have mostly given rise to the cavity.

As a consequence of that, whereas the typical stalactites and stalagmites are relatively scarce, hypogenic speleothems are remarkably abundant and exquisitely developed. These particularly unusual formations appear especially in the upper level (around -74m) and give name to the main chambers. A very nice example of that is the Bath Chamber characterised by its emerald crystal-clear lake, which is the habitat of some fragile skittish blind crustaceans.

Another example is the irreal Ghost Chamber, where fantastically coloured “clouds” drape the ceiling, while gigantic “onions” cover the ground. On their surface, the ascendant flow of CO2 bubbles has moulded the rock, creating trails of bubbles.   

Finally, the Paradise Chamber makes you feel as if you are entering an alien world. Not only is its ceiling packed with colourful “clouds”, but the ground is also covered with simple and double calcite “cones”.  Fascinated as I was when I came into this chamber, I sincerely thought I was in an alien monster´s nest.

Currently, the cave is partly closed for environmental and protection reasons – a special authorization is required to visit the cave. The “Sima de la Higuera” was nominated as a Natural Monument of the Region of Murcia, and, due to that, there is a system of regulations to guarantee the survival of this magnificent but fragile treasure. 

Marina Concepción Martín Melgarejo

Escuela Oficial de Idiomas de Murcia