First Celebration of the International Day of Caves and Karst (IDCK),
proclaimed by UNESCO

Postojna, Slovenia: 10–13 September 2026

Following the proclamation of the International Day of Caves and Karst (IDCK) by UNESCO, the first official celebration is planned to take place in Postojna, Slovenia, in September 2026.

The central date of the celebration will be 13 September 2026, with a series of scientific and outreach events planned in the days leading up to it.

Preliminary programme outline (subject to confirmation):

• 10 – 12 September 2026 – International conference in Postojna
  Theme: Sustainable management of caves and karst, with a focus on protection, education and research as a foundation for sustainable development, and scientific excursion to selected karst and cave sites
• 12 September 2026 (Saturday evening) – Official IDCK celebration event in Postojna Cave (to be confirmed)
• 13 September 2026 – International Day of Caves and Karst

Details regarding the conference programme, invited speakers, co-organisers and registration will be announced in due course.

Organisers (preliminary):

• with the support of the Slovenian National Commission for UNESCO
• International Union of Speleology (UIS)
• Karst Research Institute ZRC SAZU, Slovenia
•  …..

We warmly invite all supporters of the International Day of Caves and Karst initiative, as well as the wider scientific, educational and policy communities, to save the date. A formal announcement, registration form and detailed programme will follow.

Nadja Zupan Hajna
For the Organizers

Postojna, 14.1.2026

Further information will be available on the websites: https://uis-speleo.org/; https://www.caveskarstday.org/; https://izrkp.zrc-sazu.si/en

At today’s General Conference of UNESCO in Samarkand (12 November 2025), 13 September was officially proclaimed the International Day of Caves and Karst — a global recognition of the significance of the hidden world beneath our feet.
The initiative was proposed to UNESCO by the Republic of Slovenia, following the proposal of the International Union of Speleology (UIS), in close cooperation with the Slovenian National Commission for UNESCO, the Permanent Delegation of Slovenia to UNESCO, and the Karst Research Institute ZRC SAZU, where the UIS headquarters has been based in Postojna, Slovenia.
Caves and karst cover nearly one quarter of the Earth’s land surface and provide drinking water to over a billion people. They preserve unique subterranean biodiversity, geological archives, and invaluable cultural heritage. Yet, they remain among the least understood and most fragile ecosystems on our planet.
The International Day of Caves and Karst will help raise global awareness, promote research, education, and international cooperation in science, environmental protection, culture, and sustainable tourism.
The UIS warmly thanks all UNESCO Member States that supported the initiative, as well as the UNESCO scientific programmes (IGGP, MAB, IHP) and international partners including the International Science Council (ISC), IUCN, and more than 150 organizations worldwide that endorsed the proposal. Our sincere appreciation goes to the Slovenian National Commission for UNESCO and the Permanent Delegation of the Republic of Slovenia to UNESCO in Paris for their dedicated diplomatic efforts and continuous support.
From now on, September 13 will unite the global cave and karst community in celebrating and protecting these vital landscapes — for science, for nature, and for humanity.
Don’t forget, in 2026 we will celebrate the first ever International Day of Caves and Karst on 13 September!

Nadja Zupan Hajna, UIS Past President

To learn more, visit:
International Day of Caves and Karst website: https://www.caveskarstday.org/

Join us and celebrate the International Day of Caves and Karst – IDCK!

This September 13th, we are thrilled to announce that the speleological community will celebrate the International Day of Caves and Karst for the first time. This unique event, approved by the UIS General Assembly during the 19th International Congress of Speleology in Belo Horizonte, Brazil, is a momentous occasion for all of us.

The International Day of Caves and Karst (IDCK) is a proposed UNESCO-recognised annual observance on September 13th, dedicated to raising global awareness of caves and karst landscapes. These environments, which provide vital resources and preserve unique biodiversity, have a profound impact on a global scale, including supplying drinking water for over a billion people. They also hold invaluable geological and cultural records, making them a treasure for humanity.

So, we invite you to join us and celebrate the wonderful world of caves and karst. Your participation, along with that of your organizations and countries, is crucial in making this event a success and in raising awareness about these unique environments.

For more information, visit: https://www.caveskarstday.org/

The 2025 Prize
This year, although very different, the topics addressed by the candidates were treated by highlighting a wide range of options such as raising awareness of caving, the protection and conservation of caves and karst environments, the concomitance between exploration results and scientific research, education and tourism without forgetting to identify ways to perpetuate their objectives.
The members of the 2025 France Habe Prize Jury rated each submission using an evaluation grid covering relevance, presentation, interdisciplinarity, photography, scientific content, readability and originality.

For 2025, the choice of the Jury was not easy given the quality of the six works submitted. Finally, the Jury decided, unanimously, to reward Laurent Bruxelles from France and his team for their project «Gcwihaba cave» – Bodsuana.

The 2025 France HABE Prize will be endowed with the €300 allocated by the UIS, the € 300 equipment offered last year by RESSEG, a set of two powerful lamps worth a total of $200 offered by CYANSKY, and now a set of three high-quality bags worth $250 offered by BANHAR.

The details of the project will be presented by the winner in the next UIS Bulletin.

The Jury congratulates particularly all the authors and contributors for their dynamism in speleology and their investment in the protection of caves and karst.

Origin of the prize
The France HABE Prize has been awarded since 2013 by the International Union of Speleology (UIS) to promote the protection of karst and caves for future generations. Their natural heritage is a proven source of increasingly rich information about the history of our planet and humanity, enabling people to act more thoughtfully, effectively and sustainably for the future of our environment.

On the proposal of his successor, the award is named in memory and honour of Dr France HABE († 10/12/1999) from Slovenia (Yugoslavia), who among her many occupations and achievements, among others, served as President of the ISU Protection Department from 1973 to 1997.

List of the France Habe prize winners
2013  Thomas Arbenz Switzerland for “Cave pearls of Meghalaya”,
2014  Verband der deutschen Höhlen-und Karstforscher Germany for“Cave animal of the year 2014″.
2015  Ciudadanos del Karso Puerto Rico for”Puerto Rico’s Karst Physiography Protection and Conservation Act”.
2016  Commission Wallonne d’Etude et de Protection des Sites Souterrains (CWEPSS) Belgium for “Atlas du Bassin du Hoyoux – 6e volume des Monographies karstiques par bassin versants”.
2017  Ir. JUNIAT Irawati Indonesia for the “Protection and management of karst regions in Indonesia”.
2018  The prize has not been awarded.
2019  Guglielmo RONAGHI Italy for “Light in the dark” (film).
2020  Olivier Testa, Vincent Rouquette Cathala et Phillip Lehman Dominican Republic for “Somos los cenotes project”.
2021  Speleological Group of Villacarrillo (GEV) Italy for “Our friends bats”.
2022  LA VENTA – Associazione Culturale Esplorazioni Geografiche Italy for the “Puerto Princesa underground river – Palawan – Philippines”.
2023  Daniel Caron Canada for “Centre d’interprétation du monde souterrain – Caverne de Saint Léonard –  Montréal».
2024 Paul De Bie Belgium for the monograph project “La Magne souterraine – Le système Wuinant-Haminte et autres phenomena karstiques de la vallée de la Magne”

Jean-Pierre Bartholeyns
UIS Karst and Cave Protection Commission
President

The International Union of Speleology (UIS) is pleased to announce that our official proposal for the proclamation of an International Day of Caves and Karst (IDCK) has been formally reviewed by the UNESCO Secretariat.
The Republic of Slovenia, in coordination with UIS, is actively working to secure co-sponsorship from UNESCO Member States.

We now need your help! Please:
Inform your national UNESCO delegation or relevant government authorities about the IDCK proposal.
Kindly request their support during the voting process at the  Executive Board (September 2025) and at the General Conference (November 2025).

Let us come together to give caves and karst the global recognition they deserve—for science, for nature, for culture, and future generations.
Spread the word, share the poster, and help us gain momentum!

Following the successful International Year of Caves and Karst 2021 (celebrated in 2022), the International Union of Speleology (UIS), with the support of the Slovenian National Commission for UNESCO, prepared a formal proposal to UNESCO to proclaim:
13 September as the UNESCO International Day of Caves and Karst (IDCK) – a global observance dedicated to education, conservation, and raising public awareness about caves and karst landscapes.

Why 13 September?
No other international observance currently takes place on this date.
It does not favour any nationality or organisation.
On this date in 2021, caves and karst were presented at UNESCO for the first time (although UIS itself was established on 16 September).

Current Status (June 2025)
The UIS proposal for the proclamation of the IDCK has been formally reviewed by the UNESCO Secretariat.
The initiative has already received written endorsements from 12 international organisations, 7 regional organisations, 34 UIS member countries, 81 national organisations and institutions.
On 29 May 2025, the Government of the Republic of Slovenia officially adopted a decision to support the UIS initiative. The Republic of Slovenia is actively lobbying to secure co-sponsorship from other UNESCO Member States.

Next Steps
The proposal is scheduled to be submitted to the UNESCO Executive Board by the Government of Slovenia. A final decision is expected during the UNESCO General Conference, November 2025.

How You Can Help
If possible, please inform your national UNESCO delegations or government authorities about the proposal and kindly request their support during the voting process.

We are glad to share with you Volume 67-1 of the UIS Bulletin. The PDF Interactive format can be downloaded by clicking on the link: http://uis-speleo.org/wp-content/uploads/2025/06/UIS-Bulletin-67-1-June-2025.pdf

The 41pages of this issue bring the following topics:

TABLE OF CONTENTS
• Editorial: “The UIS Bulletin and its Editors: Evolving Every Cycle”
• President’s Column: “Milestones and Momentum: 60 Years of UIS, the 19th ICS, and the Future with IDCK”
• 19th ICS 2025 – Message to the participants
• 19th ICS 2025 – State of the Art of the organization and perspectives
• 19th ICS 2025 – Keynote Lectures scheduled
• 19th ICS 2025 – List of Sponsors and Supporters
• Arts and Letters Commission – Report of first UIS Photo Contest
• International Meeting of Speleologists under UIS Patronage (Czech Republic)
• Caving in the Islands of Malta (Europe)
• Shtares Expedition 2023 (Albania) – Supported by the UIS
• Spring Project Supported by the UIS – Monitoring Microplastics
• Bulletin Bibliographique Spèlèologique/Speleological Abstract
• UIS Membership Survey 2024: How many speleologists are there?
• UIS Bureau 2022/2025
• List of UIS Member Countries
• Annual Contributions and Bank Account
• Calendar of Events

We appreciate your comments and suggestions to improve upcoming issues.

The UIS is calling for its 2025 prizes, to be assigned and celebrated during the 19th International Congress of Speleology, to be held in Belo Horizonte (Brasil) from July 20 to 27, 2025.

All cavers are invited to participate to the different categories of prizes. Instructions and details are in the following PDF file. Please note that the deadline for nominations is June 30, 2025.

The new UIS Bureau will be elected during the 2nd General Assembly of the International Congress of Speleology on 27 July 2025 in Belo Horizonte, Brazil.

Interested candidates are kindly invited to submit their application no later than two days before the election via email, using this form

This is a unique opportunity to contribute to the global speleological community.

The 19th ICS is approaching.
More than 1,000 people from 50 countries have already registered and 461 papers were submitted.

The Third Circular brings many important information about the event, the host city, the technical-scientific and social programs as well.

Detailed maps of the venue and a general Congress schedule overview are also included.

For those who haven’t yet registered, prices are still attractive.
Until May 15th, the fee is 66.6% off. Take advantage!

Visit the 19th ICS Website: https://www.speleo2025.org/
To access the Circulars: https://www.speleo2025.org/downloads/circular