On 13 September 2026, the world will celebrate the International Day of Caves and Karst (IDCK) for the very first time following its proclamation by UNESCO.
This is a unique opportunity to raise awareness of the importance of caves and karst for water resources, biodiversity, science, cultural heritage, and sustainable development.
The official international celebration will take place in Postojna, Slovenia (10–13 September 2026):
//izrkp.zrc-sazu.si/en/dogodki/international-day-of-caves-and-karst-idck

But IDCK belongs to everyone!

We encourage all UIS Member Countries, national societies, UIS Commissions, show caves, geoparks, biosphere reserves, universities, museums, schools, protected areas, NGOs, and local communities to organise their own IDCK activities around 13 September.

Whether you organise a lecture, cave tour, exhibition, school event, clean-up campaign, or social media activity, every event helps raise awareness of caves and karst.

Please register your planned IDCK events with the UIS. After your celebration, send us a short report and a few photographs so that we can showcase IDCK activities from around the world on the UIS and IDCK websites and social media.

The official launch of the UNESCO IDCK will take place in Postojna, Slovenia under the honorary patronage of the President of the Republic of Slovenia, Dr Nataša Pirc Musar, and under the patronage of UNESCO, with the support and cooperation of the Slovenian National Commission for UNESCO, Postojnska jama, Škocjanske jame, the municipalities of Postojna and Pivka, and the Slovenian Speleological Association.