Dear colleagues,

We are pleased to invite you to participate in the events marking the first celebration of the UNESCO International Day of Caves and Karst, to be held in Postojna, Slovenia, from 10 to 13 September 2026.

These events represent the symbolic and official launch of the global observance of the International Day of Caves and Karst, proclaimed by UNESCO in 2025. Please find attached the invitation and the preliminary programme of events, which will be held 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, Postojna Cave, Škocjan Caves Park, the Municipality of Postojna, the Municipality of Pivka, and the Speleological Association of Slovenia.

For more information and registration for the scientific conference and the official ceremony in Postojna Cave, please visit:

https://izrkp.zrc-sazu.si/en/dogodki/international-day-of-caves-and-karst-idck

Information on registration for the accompanying events, along with their detailed programs, will follow.

We look forward to your participation and to celebrating the beginning of this important global initiative together.

Kind regards,

Nadja Zupan Hajna

on behalf of the Organizing Committee

Karst Research Institute ZRC SAZU and International Union of Speleology (UIS)