April 15, 2022
A cave next to Nerezin Dol, photo: Čisto podzemlje (Clean underground initiative)

I write this because I am worried and writing raises awareness. Underground caves are important and should be preserved. It is sad to know that most of them around the world are threatened. I want to thank Dora, from Rent a Local team for all the support she has been giving me. I started this post thinking only about Mexico and she drew my attention that this is a bigger problem than I wanted to realise. Around the world there are so many caves and so many many threats to them. I will write about our two main interests: Croatia and Mexico.


Pollution of caves due to human activities is a big problem. In Croatia, as well as in other countries, people throw trash into caves. I do not mean a small gum paper or a plastic bottle (which I still think are not nice things to do). But, I am referring to municipal and construction waste, tires, carrion of cattle, pets, etc.

photo: Čisto podzemlje (Clean underground initiative)

More than half of Croatia caves are located in the Velebit, which adds to its natural beauty and the need to preserve the place clean and healthy. Caves can have vertical entrances or a small inclination that makes them almost horizontal to the ground. The exploration techniques depend on the type of entrance. It is not advice to go on exploring if you do not have the necessary training. Although it is extremely interesting, it is also dangerous.

Not exploring does not mean not knowing what is inside. According to “An Overview of the Cave and Interstitial Biota of Croatia” (2002) the caves are home of plenty of endemic species. In the entrance there can be easily found loads of plants that have limited growth due to light, humidity and temperature conditions. The deep you go the less vegetation you will see. Still, there is a lot of life inside. For example, small animals, such as spiders, insects and other invertebrates. There are plenty of fungi in caves and further research to know more about the species, types and particularities is needed.

Modrica Vrulja, photo: Čisto podzemlje (Clean underground initiative)

Caves are also an important source of potable or drinking water. We should preserve these natural places as cleanly and as healthy as we can. Luckily since 2015 Clean underground fights waste disposal in the karst underground by organising cleanups and raising awareness to the problematic at hand. It is a huge enterprise, if you visit their webpage you will find a map of the polluted caves registered so far. It is scary to see the map with so many red dots. The trash in the caves is both recent and old, there have been recoveries of artillery shells from the Second World War.

Modrica Vrulja, photo: Čisto podzemlje (Clean underground initiative)

It is extremely important to do something. According to the initiator of the Clean Underground initiative, Ruđer Novak: “What we throw into our abysses, sooner or later we will drink in a glass of water on our own table!”. We must keep this in mind, but at the same time if we see the big picture we can think about all the lives that are threatened by polluting caves. There are so many plants, fungi, spiders, insects, molluscs… They deserved to live! How to help? (1) Disposing our trash properly, you can check a quick guide here. (2) If you feel like donating for more cleanups. (3) Talk about it, raising awareness is immensely important.


For a few months now there's been a project in Mexico for a tourist train south of the country. It seems like a good way to increase the wealth of the country and to motivate foreigners to visit (not that Mexico is not great right now and has loads of tourism). One of the main problems with this project is the ecological impact it will have. It will cross through the Maya lands, jungle and cenotes. This means that lots of animals will perish, including the great Mexican cats, the jaguars, already a threatened species. Also, this implies that cenotes might collapse.

photo: Fran Davids

This train would be on the Yucatán peninsula, which has a chain of underwater caves called cenotes. These are water sinkholes that have been around for centuries. The ancient Maya used them for sacred purposes, in some cenotes it is possible to see archeological evidence of human activities, such as pottery, ceramics or human remains.

There are several types of cenotes, open (with a clear entrance, sort of a lake), semi open (part of it can be accessed through land and the other by diving), and underground (only accessible through diving). Cenotes can have fresh and salt water in them, in some it is possible to see the contact between both, called halocline, that creates an interesting visual effect.

photo: Fran Davids

Cenotes also provide insight to the past as in some of them there are fossils, there’s one that comes to my mind with the skeleton of a giant sloth, but there are others with mastodons and mammoths. For the Maya culture these places could be gates to the afterlife, therefore they threw valuable objects in them. These objects cannot be found anymore due to robberies or because they were retrieved by archeologists to study them. So far there are more than +10,000 known cenotes, not all of them have been extensively explored. The widest record of them has been done by groups of expert cave divers that work together to explore under safe conditions.

photo: Fran Davids

Wouldn’t you prefer to dive in the cenotes rather than destroy them? To dive in is possible! You need some training though. Learning is a great way to keep our minds and bodies healthy, so plan a vacation to the Yucatán peninsula in Mexico and explore nature. Feel free to contact Dive Life, amazing divers who are knowledgeable and eco friendly. I learned how to cavern dive with Fran Davids, who has more than 20 years of experience. I was nervous and he made me feel safe. All of the divers I know are chill people who love nature and pick up trash from the water whenever possible.

photo: Fran Davids

But if diving is not your cookie, you can also swim in the cenotes. There are no currents in them so it is quite easy to swim around. The water is usually cold, which is refreshing in the hot weather of south of Mexico. But again, if swimming is not for you, you could take some pics. There are photoshoots there that look so good, for this I would recommend Romad Photography. Remember that the best way to travel is enjoy what nature offers, leave no trace and take nothing but memories. Thus, you can plan your next vacation in Mexico and enjoy cenotes, dives and pics!

Our blog associate Alejandra Gotóo (1991) has studied English Literature and recently graduated with a Masters of Social Anthropology. Her dissertation on COVID-19 and its effects on the mind and body of Mexican physicians will be published soon. She usually writes in Spanish and has been published in Spain, Mexico, Colombia and Peru. Her topics of interest include nature, adventure, language, books, food, culture, animals, conservation, and women's rights.

We'll reply within one workday

You can find our offices in Zagreb (address: Šenoina 8) and Split (address: A. G. Matoša 56). Our network of local assistants is widespread all across the country - no matter where you are, we can provide local assistance!
©2020 by Rent a Local.