Since antiquity, humans have been utilising, living in, and sometimes hiding in underground spaces, and our fascination with them is just as old.


Caves are natural underground spaces that are formed by any of several geological processes. Some caves may have been adapted and modified for human use. These can range from the tiny recesses to the gigantic multi-mile systems such as Mammoth Cave in the United States. The forms of caves, are as varied as the geological environments in which they form.

Stalagmite in Postojna caves, Slovenia

A common type of cave is created through the dissolution of limestone, marble, dolomite or gypsum by slightly acidic water. This is typical for the karst landscape found for instance in South-West Slovenia, the Karst or Kras region that has given name to this particular topography. Other regions also have karst topography; see #China and #Vietnam below.

Caves can also be formed by erosion caused by ocean waves (often helped by frost weathering), often referred to as sea caves. Due to the post-glacial rebound (rise of land masses) sea caves are also found on dry land. One striking example is the "Hole in the hat", the cave right through the hat-shaped Torghatten summit in Nordland, the hole is now 110 meters above seal level which corresponds to sea level during the ice age.

Not content with natural caves, humans have constructed or expanded countless works underground from galleries and pits for resource extraction, through to contemporary engineering mega-structures. These are dealt with in separate guides.

Get in

Torghatten summit with hole is a landmark in Nordland.

The easiest natural underground works to access are tourist show caves, many of which have had tourist facilities installed specifically to aid access by visitors.

True 'caving', as considered by the many clubs that exist, requires an extended amount of specialist knowledge and expertise as well as demanding minimum fitness level. In addition it will certainly require the traveller to purchase specific technical equipment. For those that clearly understand and fully respect the risks it can be highly rewarding, but as with any extreme activity, the traveller must know their limits. If you have ANY doubts as a traveller as to your fitness, both physically and mentally, stick to Show caves and underground works CLEARLY open and adapted for the casual tourist.

Viewing natural caves that are not clearly adapted for tourits vists will depend on a number of factors, such as your fitness level, tolerance of discomfort level and the goodwill of owners and authorities to let you enter or explore the caves and works your desire leads you to. Visiting these sites will involve careful research. Obtaining the all important permission and consent of not only landowners, and the owners of the cave or works, is vital, as is obtaining in advance any relevant official permits from governmental agencies.

Military defence facilities (even if seemingly abandoned or out of use) often remain highly sensitive sites. An unexpected or unannounced visit could at best lead to a lengthy interrogation, with considerably worse outcomes depending ultimately on the mood of the personnel you encounter. You should make formal contact in writing with the relevant military authorities as soon as you have firm travel plans. Do not be disappointed if a planned or agreed visit has to be cancelled or curtailed for operational and security reasons, or if you are curtly refused with no reason at all.






Czech Repubic




A limestone formation in Sophienhöhle


The following areas are considered the caving regions of India: Andhra Pradesh, Chhattisgarh, Haryana, Madhya Pradesh, Meghalaya and Uttarakhand. There are literally thousands of caves in India. There are caves that are man-made (rock cut), others which are religious sites (with or without temples), archaeological sites representing early human life and finally natural caves to explore. Those marked with the symbol
are listed in the UNESCO World Heritage List.
Amarnath Cave
Belum Cave





Norway's bedrock is generally very old and hard, with only limited occurrence of karst landscape. The Rana, Saltdal, Sørfold and Tysfjord areas in Nordland have some very long and deep caves in the marble bedrock. These were only recently surveyed. The longest known cave is 25 km, the deepest about 600 meters. These caves are mostly for skilled cavers with appropriate equipment. Norway also has a handful of caves dug by ocean waves in harder rock.

Troll's Church near Molde, Norway




Slovenia is rich in caves due to the wide limestone bedrock in the South West, the Karst or Kras region that has given name to this particular topography.



Gates of Hell

United Kingdom

The UK has a number of show caves, some of which are promoted by a trade association here, amongst them being Wookey Hole, Kents Cavern (Torquay) & Poole's Cavern (Buxton).

Caving in the United Kingdom

For the traveller wanting to experience more difficult caves, or true "caving" as considered by various clubs which exist in the UK a considerable degree of skill and fitness is required, as well as suitable equipment. According to the British Caving Association there are five major caving regions in the UK, being the Yorkshire Dales, Peak District (both part of the Pennine ridge), South Wales, Mendip, Devon and Assynt (in Northern Scotland). This is not however exhaustive, given it mostly reflects the limestone caves around which caving in the UK developed. Detailed information can be obtained from specialist caving organisations.

United States




If you are permitted take simple photos, take them. You should however be aware that taking photos in low light will require a 'fast' sensor and/or a fast lens. Many shots in a cave will be easiest with a wide-angle lens. Seek appropriate local advice if you wish to use a flash.

Bat watching

Some caves are a habitat for bat species, and with careful planning you may be able to on the surface view the bats leaving a cave (which serves as a roost). Viewing bats leaving their roosts is best done as part of an organized group or with an experienced guide who will be able to advise on how to view without disrupting the normal pattern of the bats, who can be unduly disrupted by lights, noise or certain electronic devices.

Cave Diving

Not all caves are above water.

However, Cave diving is definitely NOT for the inexperienced or faint of heart, as diving in nearly all caves (and especially those involving confined spaces), is ONLY for the dedicated specialist; requires months if not years of careful planning, training and certification way beyond what an open-water certification covers; has even higher fitness requirements and should under NO circumstances be considered (let alone attempted) without the expertise and co-operation of existing and respected cave diving specialists familiar with the sites you want to dive. With cave diving there is ALWAYS the risk that you cannot easily surface in the event of a problem.

If however you have the appropriate expertise (and attitude) then the rewards of underwater caves can be just as spectacular (if not more so) as land based ones, and conventional open water dive experiences.

A somewhat counter-intuitive problem arises when you find yourself on a (relatively) dry surface again after diving some distance. Sometimes the gases that accumulate in caves are carbon dioxide or methane, both of which are not breathable and odorless, so keep your breathing equipment on.

Stay safe

Opening at Refsvik cave at Lofoten

(see also Urbex#Stay safe)

There are few risks associated with show caves clearly adapted for tourism, and if you have any doubts as to your ability or fitness (including mental attitude), sticking to these is very strongly recommended.

In order to stay safe when visiting caves, It is vital to know as much as possible about the specific cave you wish to visit in advance, so you can plan accordingly.

Caves where access, upto and including the entrance, involves tight crawls; confined space; vertical drops; sharp climbs; any expanse or mass of water or in general where a failure of any equipment is going to become a critical problem, are considered beyond the scope of accessibility for the non-specialist. For safety advice concerning visiting these caves, specialist advice will need to be obtained from dedicated caving and subterranean exploration organizations, familiar with the specific site concerned.

For other reasonably accessible caves, noting the previous paragraph, which are not as well adapted for the tourist or traveller (if at all), you should seek and heed local advice even if the cave seems easy at a cursory glance at the surface or entrance.

There is some detailed advice on cave safety at this site but some common sense follows:

Know the cave (and system) and your exit before you enter, and if the cave has more than one entrance or exit, know which ones will be safe to use. Practically all responsible cave explorations are planned only after weeks or months of research.

NEVER enter a cave alone, because not only will there be no-one to get you out, but no-one will know where you are! Responsible cavers work in groups of at least four, and as well as lodging their plans with appropriate contacts, will in nearly all circumstances have a surface watchman whose responsibility is to contact the authorities if things go bad or a group below the surface fails to return by a specified time.

Caves are naturally dark, and without artificial light you will have a hard time navigating them. Don't rely on a single light source, which could fail. Spare light sources are strongly recommended.

Check the weather first! Underground rivers form part of many caves (and it is these which in many cases helped the formation of the caves). In wet conditions, the levels of these rivers can change rapidly, limiting or cutting off access routes between parts of the cave system and the entrances. Getting caught in a cave with a rising flood isn't worth it.

Not all caves have stable or reliable floors. Loose rock, gravel, and even sand can exist. In addition in 'wet' caves there may be fungi or moss or lichen, rendering both walls and floors slippery. Floors may be uneven, and there can be unexpected deep openings or cracks.

DO NOT under under any circumstances enter any underground expanse or mass of water, without having in advance sought appropriate advice. (Not only can the depth be deceptive, but the water in caves may not be as pure as its appearance suggests). Caution should similarly be exercised in respect of moderate mud; silt; and rock or scree falls.

Stay healthy

There are no particular health risks in a well-managed show cave, but actual spelunking exploring caves that are not set up for easy visiting does carry some risk. The main tactic for reducing it is to seek advice from knowledgeable locals; often hiring a local guide will be wise.

Bats can carry rabies and rabies vaccination is recommended for spelunkers likely to encounter bats. It is also recommended for all travellers in certain countries, and for those who will spend time in rural parts of others. Anyone planning a major trip should consult a doctor, preferably a travel medicine specialist, beforehand and rabies vaccine may be a wise precaution for many.

Animal droppings, in particular bat guano which collects in large amounts is some caves, can spread an infection called histoplasmosis; the cause is a fungus which grows in the droppings and releases spores when disturbed. In many people this infection has no ill effects, but in some cases it can be fatal if left untreated. Antifungal medications are effective against it, but it is better to avoid the infection by giving guano a wide berth.


Be respectful of the underground environment you are visiting. Ideally you should try to leave the underground environment as you found it as far as possible. No garbage and human waste should be left behind. Many flora and fauna are adapted to the underground environment, so the overuse of lights or camera flash can disrupt some fauna. The very presence of human beings and light can also severely change the micro-climate and problems like Lampenflora or plants growing due to the light and warmth of artificial light sources are a serious problem in some caves. Some natural caves include unique prehistoric cultural heritage and care must be taken to preserve this for the future.

Many caves are also home to bats, which in many jurisdictions are a protected species, and interference with them should be avoided in nearly all circumstances. It is not unusual for caves in some regions to be closed over that region's fall and winter seasons in order to ensure hibernating bats don't wake up too early due to human influence.

See also

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