The guided tour starts with an explanation on how the caves came into being.
The 17,032 km of tunnels have three main levels. The first level is about 1 metre underground and has an average of 30cm across. Level two, the one we will visit, is about 3 to 4 metres underground. It has an average diameter of 3 to 4 metres. The third and deepest level is 13 metres deep and has an average diameter of 5 metres; however, this descends to 50 metres.
The three levels are connected by fissures, offshoots and cracks. Most tunnels are about 3 km long and have side tunnels which go for about 500 meters, to reach all of the 17 km of volcanic tubes. The “Cueva Del Viento” is the fifth longest in the world after the four longer ones, all in Hawaii. However, in maze and complexity Tenerife scores best! You can compare the underground of Icod de los Vinos, which stretches all the way to the coast, with a Gruyere cheese! In addition, the tubes in Hawaii are only 30 years old in contrast to the Tenerife ones, which are more than 27.000 years old!
The whole complex is composed of lava as a result of an eruption from El Pico Viejo (old crater) on the eastern slope of Mount Teide some 27,000 years ago and added to by later activity.
Lava usually leaves the point of eruption in channels. These channels tend to stay very hot as their surroundings cool. This means they slowly develop walls around them as the surrounding lava cools and/or as the channel melts its way deeper. These channels can get deep enough to crust over, forming an insulating tube that keeps the lava molten and serves as a conduit for the flowing lava. These types of lava tubes tend to be closer to the lava eruption point.
Further away from the eruption point, lava can flow in an un-channelled, fanlike manner as it leaves its source, which is usually another lava tube leading back to the eruption point. Called pahoehoe flows, these areas of surface-moving lava cool, forming either a smooth, rough or rope like surface. The lava continues to flow this way until it begins to block its source. At this point, the subsurface lava is still hot enough to break out at a point, and from this point the lava begins as a new "source". Lava flows from the previous source to this breakout point as the surrounding lava of the pahoehoe flow cools. This forms an underground channel that becomes a lava tube.
Such drained tubes commonly exhibit step marks on their walls that mark the various depths at which the lava flowed. This is called “Terrazas” (fluctuation levels of lava depending on the time it has been).
Armed with this new knowledge, we were handed a speleologist helmet and the trip began.
A mini bus dropped us off at 585 metres above the sea level on an abandoned area of cultivation, which was known as the village of “Huerta de Cholugo”.
The guide explains to us that speleologists and ecologists have been working on this area and the caves since 1994, to restore the area as much as possible. Most of them were covered with lichenin and earth.
It was a nice surprise to receive some historical information on the walk to the caves.
Apparently, this secluded village was, until 80 years ago, still producing, an average of 800 bags of potatoes every year. Nice paths make it heavenly to walk through this place.
The area is richly covered with rock roses, plum trees, Acebiños (holly trees), representative plants of the Laurisilva (laurel forest) and Torviscas.
The trunk of the Torviscas is used for wicker handicraft.
Some ruins of the farmers houses are still intact enough to learn about their building techniques. The walls are made of lajas (big pieces of lava) which were collected from the surrounding area. One house still has some of its roof left, this shows us that the people of that time already had the ability to bake the red roof tiles.
Not only were the houses handmade, but also the ancient royal path “Caminos Reales” was put down stone by stone. The royal path was the only way to transport food, wood or ice from the “Cueva del Hielo” (Ice Cave) The width of the royal path is exactly the size of two loaded mules. The side walls of this royal path, provide an excellent habitat for lizards and many other species.
Higher up the Royal path we enter the caves. This is what we came for, and I have to admit that I felt just a little bit excited. Entering to the “Cueva del Viento” we were getting an insight into the role of lava flows in a volcanic eruption. We saw the whimsical forms sculpted by the lava in the bowels of the earth. It is a fine example of the complexity of geology, with beautiful geo-morphological phenomenon like chasms, terraces and other lava formations.
The tunnel has white and orange colours. The white colour is silica, gypsum and the orange one is iron oxide. Lava stalactites called lava cycles are rare in lava tubes. However, short lava cycles were all over this ceiling. It was formed as the lava in the tube retreats and the viscous lava on the ceiling drips as it cools. Dripstone is created when lava splashes on the inside walls of the tubes.
As I am scared of rats and mice, I could not resist asking about the life in these dark deep tunnels. We were told that there are 172 species, 52 are true troglobionts, most of them endemic to this cave. A troglobite is an animal that spends its life entirely in the darkest parts of caves. Such creatures have become specifically adapted for life in total darkness and over time they have evolved to develop improved senses of smell, taste and vibration detection, while losing anatomical features that are superfluous without light, such as functioning eyes and pigmentation. The spider Disdera Esquiveli, the beetle Oromía hephaestos and the cockroach Loboptera are three of them.
Ok, now the guide has got my attention! I start to explore every centimetre for unwanted companions! Just a few minutes later, I am first to discover, a black spider dangling right above us! Without the light of the helmet, you would never know she was there. Moreover, she was not alone. Many more live in these tunnels! Luckily, they are more scared of us, than we are of them.
We also saw many cracks and micro cracks in the ceiling. This is the result of retraction. Roots of plants find their way all the way down to these tunnels through these tiny little fissures.
As we continued our tour inside the cave, we could see the complexity of many side tunnels and crawl ways. This underground complex is a mysterious labyrinth if you ask me. We walked deeper and deeper into the cave to a point where no more daylight could enter, the guide then asked us to cut all the lights and be silent for 30 seconds.
You can call my partners and I irrational, but the three of us agreed that it was a very mysterious moment. There was nothing to be scared of, but it was still… weird!
When we put on the lights again, I took some more pictures and yes… I caught sight of a mystery figure! The shape of a man appeared for just 2 seconds. I was shocked and quickly took a second picture ,but it was gone! However you can see for yourselves. On one of the pictures, the shape of a face is clearly visible for all to see.
I feel privileged to have experienced this unexplainable few seconds, because this made our visit to the Caves of the Wind special!
Practical information:
Since 20/06/08, the Cuevas del Viento tubes are open to the public but on reservation only. Until the end of December, the entrance ticket is 6,00 € and at 3,00 € for residents and/ or children. The price will be adjusted in January 2009.
History
In 1776 the brothers Bethencourt de Castro entered the cave of San Marcos to measure those tubes. They discovered that the tunnels continued all the way to Mount Teide.
In 1891 British Speleologists made a map of the caves. During their exploration they found aboriginal burial sites, which are now in the Natural History Museum.
In April 1969, the first modern exploration took place. This was done by the Sección de Exploraciones Vulcanoespeleológicas de La Guancha.
In 1973 a crawl way (later known as the “El pozo de los ingleses”) took British speleologists up to the union (or joint) of the medium and lower level.
1994, September the 20th the area of Cueva de Viento-Sobrado was declared a Natural Monument. This area is now protected from any building projects.
How the Caves came to be called Cuevas del Viento
There are thermometers and hydrometers both outside and inside the tunnels. The cave has seven entrances, and a rather high difference between upper and lower entrances. As a result air is flowing through the cave forming convection cells. In winter the cave is warmer than outside and the warm air leaves at the upper entrances, in summer the cold air flows out of the lower entrances. That is the simple reason why the cave is called Cueva del Viento or Cave of the Wind. Oddly, at every entrance there is a fig tree.
* Icod de los Vinos is well known for its huge Dragon Tree “El Drago Milenario” and for its famous wines.
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BUILDINGS AND PLACE IN TENERIFE