Norbert Marwan (@pucicu.de)

International Day of Caves and Karst (IDCK) First celebration of the UNESCO International Day of Caves and Karst in Postojna 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.PRELIMINARY PROGRAMME (10–13 September 2026)10–13 September 2026: International Scientific Conference in PostojnaTheme: Sustainable management of caves and karst, focusing on protection, education, and research as the foundation of sustainable development.10 September (09:00–17:00): Excursion 1 – Škocjan Caves and the Pivka Intermittent Lakes11 September (09:00–17:00): Full-day conference (keynote lectures and participant presentations; Postojna Cultural Centre)12 September (09:00–14:00): Half-day conference (keynote lectures and participant presentations; Postojna Cultural Centre)13 September (10:00–17:00): The Most Important Karst Spring – the Unica spring (IAH/MIKAS event); Excursion 2 – entrance section of Planina Cave, natural bridges in Rakov Škocjan, and Cerknica Polje Škocjanske jame, photo Mark B.; Planinsko polje, photo Jurij Hajna.11–13 September 2026 (to be confirmed): Meeting of Speleologists Programme in preparation; organised by the Slovenian Speleological Association (JZS)11 September 2026 (20:00): 3D caves presentation by Csaba Egri and Peter Gedei (Postojna Cultural Centre)12 September 2026 (meeting 17:15): Official IDCK ceremony in Postojna Cave (for registered participants and invited guests; tour, cultural programme, and reception)11–13 September 2026: Accompanying programme (in preparation) INVITATION Registration:REGISTRATIONThe deadline for submission of papers is June 26, 2026.The deadline for registration for the conference and ceremony is August 28, 2026. We kindly invite you to save the date. Further information will follow in due course. On behalf of the organisersNadja Zupan HajnaKarst Research Institute ZRC SAZUandInternational Union Of Spelology (UIS)Titov trg 2, 6230 Postojna, Slovenia https://izrkp.zrc-sazu.si/en/dogodki/international-day-of-caves-and-karst-idck