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Sometime between painting ceilings, Leonardo da Vinci said, “With time, and water, everything changes.” He would have got even more poetic if he’d delved deep under the Western Hajar. Here, where rock that was once ocean floor begins to build itself into Oman’s highest mountains, the Al Hoota cave system stands theatrically lit – and accessible to the tourist – for the first time.

This is the two million year story of how rock dissolves under water, and how water sculpts rock. Rock might be hard and boring to most people, but when married to water it can form the kind of concerto that Goethe described as ‘frozen architecture.’

And the best showcase of such absolute splendour is the Al Hoota cave system – comprising of the original Al Hoota cave (named after its neighbouring village) and its exit cave, Al Fallah. Ironically, although the latter is largely unknown, you are actually entering Al Fallah when you make your way in now.

The vehicle of nature
The largest chamber in the cave is as large as the Al Bustan Palace Hotel, and the entire gallery is dripping stalactites and awash with stalagmites. Everything from the ceiling down the walls and across the floor is softened into the curves of the flow of water. And there is a lot of water. While the mountain slopes above are bone dry, pieced together with the shrivelled roots of shrubs, it is estimated that the underground lake in the cave can hold more than 30,000 cubic metres of water. The main lake in the cave is around 800m long and about ten metres in width, with a maximum depth of 15m. When it rains above, surface water accumulates in the wadi to the north and floods through the cave at up to 550 cubic metres per second. Now, sensors have been fitted at the lake to warn of imminent flooding, and a backup power supply and emergency lights for the pathways have also been added.

Al Hoota is certainly as much about water as it is about stone. Water is everywhere, from the molten rock that envelopes you to the little pools that trickle down into the lake. It is, as Da Vinci said, vetturale di natura, the vehicle of nature.

But perhaps the most enchanting feature of the subterranean tank is the fact that even its dark recesses hold life. Here, where there has never been sunlight, lives a blind fish that has little use of eyes or pigment. Garra barreimiae is unique to this ecosystem, and, even more extraordinarily, lives off a by-product of oil. The oil occurs naturally in the water and breaks down to form algae that the fish eat. Such are the delights of living in the dark.

The long way round
The total length of the cave is around 4.5km, but you only have the first 500m from the southern entrance of the cave at your disposal. In this, 822m of pathway has been constructed in a circular loop, and it’ll take you around an hour to get through. A variety of techniques were used for this including concrete, elevated walkways, steel steps and bridges. 1,300m of stainless steel handrail has been installed along the pathway, with viewing platforms at key points. You aren’t allowed to get off the elevated path, and don’t come in contact with the cave floor.

Theatrical lighting
The best part of the interior is the delicate lighting that leaves most areas dark, just highlighting the key features. It has been choreographed with an incredibly light touch, and certainly added another dimension to Al Hoota. Man has traditionally viewed caves as dark and mysterious places, and they often evoke strong feelings. Limited use of lighting maintains this emotional response and also lessens the possibility of unnatural plant growth if the cave lights are left on too long.

The lighting system is waterproof, and can be operated by guiding staff using remote controlled devices. At each viewing platform, feature lights are positioned to illustrate the speleothems, or cave decorations, in the immediate area.

Television
For security and safety, closed circuit TV cameras have been installed throughout the cave. There is also the future possibility of having viewing facilities for disabled persons at the first platform inside. The concept is for disabled persons to experience the cave first hand and to allow remote control of television cameras located at several viewing platforms.

The first train in Oman
It might not be as grand as the karst topography, but the little 36-seat electric train between the visitor’s centre and the cave is also Oman’s first railway, and is as much a centre of attraction as it is a mode of transport – even if its 550m of track is consumed within minutes. After travelling the first 400m on the surface, the train enters a 150m long tunnel that has been excavated into the hill of limestone in which the southern entrance of the cave is located. A small underground railway station has been constructed at the end of the tunnel in order to allow passengers to alight before walking through an airlock doorway and into the cave itself.

How water sculpts a cave
Caves might be seemingly made of stone, but they are made by water. It all starts when rainwater dissolves carbon dioxide from the atmosphere or soil, producing a dilute carbonic acid that dissolves the limestone, creating room for itself – the cave system. Other acids like sulphuric acid (formed from sulphur compounds in organic sediments) also occur in ground water, and contribute to the process. How fast can water dissolve its way through rock? Think ten millimetres in 1,000 years. Of course, this can vary greatly, a phenomenon that fascinated Leonardo himself. As Da Vinci examined the motion of waves and currents, he was the first to postulate the principle of erosion: "Water gnaws at mountains and fills valleys. If it could, it would reduce the earth to a perfect sphere."

A typical second phase in this three-act play starts with a drop in the water table. Water, of course, moves downwards, and as its channel cuts into the rock the underground river gets deeper and the water table seeps to a new and lower level. Eventually, the first level of caves made are left above the water level.

This aeration is essential to the natural process of decorating a cave with deposits that collectively form speleothems: stalactites hanging down from the ceiling, stalagmites reaching up from the floor and other such dripstones. When water enters into contact with the air of a cave, some of the carbon dioxide in the water escapes, leaving behind a residue of calcium carbonate. Each drop of water that drips down leaves behind its signature, and the deposits build upon themselves to form the long, tapering forms we marvel at today. As the water that supplies the stalactites drips down and splatters on the floor, it too leaves behind a deposit, forming stalagmites on the ground, a counter image to the formations above.

And then came Man
While it is true that until now you could lower yourself down a drop into the darkness of Hoota, such requirements meant that most of us were content passing by, up 3,000m to the Grand Canyon and Jebel Shams.

Instead, you can now drive a couple of hours from Muscat in your saloon car, enjoy a Lebanese restaurant, sniff around a souvenir shop and rattle over Oman’s only railway line, before enjoying a walk in the cave. Soon to come: a geological museum, educational computer animations and a live show of the blind fish. Hoota might have existed for a couple of million years, but it only got comfortable by the end of 2006.

While the advent of developed tourism will forever mar the raw experience of braving the cold dark inner reaches of one of the great caves of Arabia, it is only through such efforts that more people can experience the wonders of nature, and learn to preserve it.
Even before the creation of the Ministry of Tourism, the Ministry of Commerce and Industry commissioned the Museum of Natural History Vienna, which along with Salim Abdullah al Maskery – an expert Omani geologist – undertook a feasibility study of a number of caves and karst features around 1995. This was part of a strategy to develop environmentally sustainable tourism in Oman in order to provide economic benefits for society as a whole as well as on a local community scale by offering opportunities for employment – most staff at the cave complex are not just Omani but actually come from the immediate area.

Although the sultanate has many excellent karst features, the significant environmental value of Al Hoota cave, combined with its geographic location and potential for easy access, made this a standout choice for development as the first show cave in Oman. Up to 70,000 visitors are expected to visit Al Hoota this year.

Andrew Lawrence, a specialist on karst tourism and an advisor to the Ministry of Tourism, says, “Al Hoota cave is an excellent example of the ministry’s commitment to develop ecotourism projects.

It provides direct benefit to the local community through employment and has been designed to be environmentally sustainable. The interpretation of the cave’s values to visitors by specialist lighting and guided tours is an amazing experience, which also provides an opportunity to raise awareness about Oman’s environmental treasures. By the number of student groups that have visited the cave so far it is proving to be a great educational tool, and perhaps might even give inspiration at an early age to those who may eventually grow to become custodians of these special resources.”

Planning your trip
It’s incredibly easy to get to Al Hoota cave now. Forget kilometre readings and GPS waypoints. Just get onto the Nizwa highway and follow the brown signs that point to the cave. From Muscat, you’ll be turning right into Nizwa and driving through it, towards the Hajar mountains. You’ll then turn off towards Al Hamra and then Hoota. It takes around two hours to drive from Muscat to the cave.

Al Hoota is under the management of PromoOman, under contract from the Ministry of Tourism. A little known fact is that there is a quota of 750 people allowed into the cave per day, and there is, as of now, no system of making a prior booking. The Hoota cave management can be reached at 24490060 and the very sketchy www.alhootacave.com.

* Timings of the cave facilities are from 9am to 6pm
* Cave visits are guided and last around an hour
* Mondays are off except for groups with prior reservations
* The show-cave is closed during the months of July and August
* You will need special permission to photograph inside the cave
* Some facilities haven’t opened yet – please call the complex for time-specific information

Caves of the sultanate

* Although Oman currently has a dry climate, past conditions have cycled between wet and dry periods. The relatively lus- cious vegetation that existed in previous times contributed to the amount of carbon dissolved in the water and hence its
ability to create an abundance of caves

* Much of Oman is comprised of limestone formations that rep- resent a sequence of rocks more than 5km thick, and up to 300mn years old. 100mn years ago, the site where the Al Hoota cave is now located was part of an ancient coral reef
on the sea floor

* The Majlis al Jinn on the Selma plateau on the northeast coast of Oman contains the second largest cave chamber in the world and is important for its geological and aesthetic values. Selma, the legend goes, was a young shepherdess who left her flock while she went to fetch water. She found a leopard eating her goats when she returned, and she bravely fought it off with an axe – a great battle that killed them both. For her memorial, the heavens sent down seven stars to the spot where she was found, and these became the seven caves that people from around the world now come to explore. And the village nearby, along with the plateau, are now named after their bravest ancestor.

* In the Dhofar region near Salalah is the Teyq mega doline that is the second largest doline in the world. This is a huge depres- sion in the landscape formed by underground subsidence. This is also important for its geology and as well as for its very impres- sive hydrology. In the Slovene language dolina means valley.

History of the science
Prior to the mid-19th century, the scientific value of caves was considered only in its contribution to other branches of science, and cave studies were considered part of the larger disciplines of geography, geology or archaeology. Very little cave-specific study was undertaken prior to the work of Édouard-Alfred Martel (1859-1938), the 'father of modern speleology,’ who through his extensive and well-publicised cave explorations introduced the concept of speleology as a distinct area of study. In 1895 Martel founded the Société de Spéléologie, the first organization devoted to cave science in the world.

Cave speak

Karst
Originally the name of a limestone landscape in Slovenia with particular erosional features and subsurface water drainage, which now is used all over the world to describe dissolution features. Nearly 40 per cent of the sultanate’s surface is limestone and shows karst features.

Cave
Underground natural void of a size that can be visited by a person, usually longer or deeper than 6m (otherwise it’s just a hole).

Sinkhole
Collapsed cave or doline – a hole in the surface with steep or vertical walls and a large surface opening.

Doline
Funnel shaped depression at the land surface, of which the diameter is larger than the depth, infiltration area for surface water.

Passage
Mainly horizontal part of a cave.

The difference between a stalactite and stalagmite
These are the most commonly confused terms that the general public grapples with. But it’s really easy to remember which is which: stalactites have a ‘c’ like their ceilings, and stalagmites have a ‘g’ like the ground they reach up from.

One artist on another: How water inspired Leonardo Da Vinci

"Water is sometimes sharp and sometimes strong, sometimes acid and sometimes bitter, sometimes sweet and sometimes thick or thin, sometimes it is seen bringing hurt or pestilence, sometime health-giving, sometimes poisonous. It suffers change into as many natures as are the different places through which it passes. And as the mirror changes with the colour of its subject, so it alters with the nature of the place, becoming noisome, laxative, astringent, sulfurous, salty, incarnadined, mournful, raging, angry, red, yellow, green, black, blue, greasy, fat or slim. Sometimes it starts a conflagration, sometimes it extinguishes one; is warm and is cold, carries away or sets down, hollows out or builds up, tears or establishes, fills or empties, raises itself or burrows down, speeds or is still; is the cause at times of life or death, or increase or privation, nourishes at times and at others does the contrary; at times has a tang, at times is without savor, sometimes submerging the valleys with great floods. In time and with water, everything changes."