Random Cave Name Generator

How this random cave generator works

Press Generate and you get a cave and its country. Turn up the Number box for several at once, no repeats. Copy takes them.

Mammoth Cave. Carlsbad Caverns. Postojna. Waitomo. Son Doong. Lechuguilla. Jewel Cave. Sistema Sac Actun. Sistema Ox Bel Ha. The Gouffre Berger.

Between them they contain the strangest fact in geography: caves get longer without growing.

A cave's length measures how far people have walked

When you read that Mammoth Cave in Kentucky is the longest cave in the world at more than 420 miles, or 676 kilometres, that number is not a measurement of the cave.

It is a measurement of the surveyed passage. It is the total length of tunnel that a human being has physically crawled through, dragging a tape, taking bearings, and writing it down. Everything beyond the last survey station is not in the number, whether it is a metre of passage or forty miles of it.

So the world's longest cave gets longer every year, and nothing happens underground. Volunteers from the Cave Research Foundation and other groups spend arduous weekends squeezing through mud and water, and the figure goes up. In 2021 a survey added eight more miles in a single reported push. Park officials, asked whether they were near the end, said there is no end in sight.

Every cave length you have ever read is a statement about exploration effort. A cave in a country with no local caving club is, officially, short.

The night Mammoth Cave doubled

In 1969 Mammoth Cave had 65 miles of documented passage. Impressive, and firmly the longest known cave in the world.

Nearby, under a different ridge, lay the Flint Ridge system, which cavers had been exploring separately for years. Everybody suspected the two were connected. Nobody had found the connection.

In September 1972, a Cave Research Foundation party went underground and stayed there for fourteen hours, and came out having linked the two systems.

Mammoth Cave's official length went from 65 miles to 144 miles.

Not one stone had moved. Not one cubic metre of limestone had dissolved. On a Sunday morning in Kentucky the longest cave on Earth more than doubled, because a person crawled through a hole and shone a torch into a passage somebody else had already mapped.

Since then Proctor Cave, Roppel Cave and Morrison Cave have all been connected in too. The cave keeps eating the neighbourhood.

Caves eat other caves

That is not a metaphor. It is a formal convention.

When cavers find a connection between two systems, the two become one, and speleology has a rule for what to call the result: the larger system absorbs the smaller and keeps its own name. The smaller cave stops existing as a cave. Its passages are still there. Its name is gone from the register.

Off the coast of Quintana Roo in Mexico, the limestone is riddled with flooded passages that divers reach through sinkholes called cenotes. Two systems there, Sistema Sac Actun and Sistema Ox Bel Ha, have been trading the title of longest underwater cave in the world since 2007, each one pulling ahead as its divers survey a few more kilometres.

In early 2007, Sac Actun swallowed a system called Nohoch Nah Chich.

Then in January 2018, a diving team announced they had found a link between Sac Actun, then around 263 kilometres long, and the neighbouring Sistema Dos Ojos, 84 kilometres long. Dos Ojos was famous. Divers came from everywhere to see it. It had been filmed, written about, and named.

By the rule, the larger system absorbed the smaller. Sac Actun kept its name.

Dos Ojos ceased to be a cave.

A place can be deleted by a definition

Sit with that for a moment, because it is stranger than it first sounds.

There is no cave to visit called Dos Ojos. There is a stretch of Sac Actun that used to be called that, and cenotes at the entrance that still carry the name. A guidebook printed in 2017 lists a cave that a guidebook printed in 2019 does not, and nothing whatever happened to the limestone in between.

Two people swam into the same room from opposite ends. That was the entire event. The passages are unchanged. The water is unchanged. The name is gone.

The set of things in the world is not fixed. It depends on where we have drawn the edges, and the edges move when somebody finds a door.

Which is worth remembering the next time you read that a cave is the longest, or the deepest, or that there are a certain number of them. Every one of those statements is a statement about people with torches.

Ways people actually use this

• Quizzes. Show the cave, ask for the country. Then ask what its length actually measures.
• Worldbuilding. Caves need soluble rock and moving water. Put limestone under your map and the caves write themselves.
• Travel reading. Lechuguilla in New Mexico is effectively closed to the public, and almost everything known about it was brought out by survey teams.
• Teaching what a measurement is. The longest cave in the world is the one with the most volunteers.
• Naming things. Ox Bel Ha means three paths of water. Sac Actun means white cave.

Getting more out of the filters

• Entries read "Name - Country", so Contains works as a country filter. Try USA, Mexico, Slovenia.
• Type Sistema for the Mexican underwater systems. Every one of them is flooded, and every one of them is measured by divers.
• Type Cave and notice what does not come back. A grotto, a gouffre, a sótano. English is not the only language that names holes in the ground.
• Starts with and Ends with compare one character, so give them a single letter.

Questions people ask

What is the longest cave in the world?

Mammoth Cave in Kentucky, at more than 420 miles or 676 kilometres of surveyed passage. That number rises whenever volunteers map more of it, and there is no reason to think it has stopped.

What is the longest underwater cave?

Sistema Ox Bel Ha in Mexico currently holds it, ahead of Sistema Sac Actun. The two have swapped the title repeatedly since 2007 as each system's divers survey further.

Do caves really get longer?

The caves do not. The numbers do. A cave's published length is the total passage that has been physically surveyed, so it grows with exploration, and it can jump enormously when two known systems are found to connect.

What happened to Dos Ojos?

In January 2018, divers found a connection between Dos Ojos and the larger Sistema Sac Actun. By speleological convention the larger system absorbs the smaller and keeps its name, so Dos Ojos is now part of Sac Actun and is no longer counted as a separate cave.

How many caves are there?

Nobody knows. The number depends on how much limestone has been walked over by somebody with a torch, and on where speleologists have decided one cave stops and the next begins.

References

1. Mammoth Cave system, record length
2. Sistema Sac Actun
3. Sistema Sac Actun, Northwestern University