# UNESCO International Day of Caves and Karst establishment

> Live situation record from CLSTR: https://clstr.news/situations/unesco-international-day-of-caves-and-karst-establishment
> Updated: 2026-09-13T04:14:52.000Z. Sources: 11. Developments: 2.

UNESCO has established September 13 as the first annual International Day of Caves and Karst. This designation follows an initiative by Slovenia and the International Union of Speleology (UIS) to highlight the importance of subterranean natural heritage, noting that karst regions cover nearly one-fifth of Earth’s land surface and provide drinking water for over one billion people.

On the inaugural observance on September 13, 2026, central ceremonies and an international scientific conference were hosted in Slovenia at Postojna Cave. In Croatia, the University of Zadar marked the day by presenting scientific projects focused on karst research and environmental challenges, including pollution and unpredictable water flow.

Global context highlights the vulnerability and unexplored nature of these environments. In Slovakia, karst landscapes cover approximately 5.5 percent of the territory, including the Demänová Cave System. Experts noted that only about three percent of Slovakian caves have been discovered so far, emphasizing the potential for continued scientific exploration and the landscape's essential role in water resources and tourism.

In Sicily, the ‘Man and Karst 2026’ conference brought together researchers and geologists to study karst landscapes, featuring sessions at the Vendicari Nature Reserve and visits to the Grotta Monello. Additionally, the ‘Tutti in grotta appassionatamente’ initiative in Palermo aimed to educate the public on the biodiversity and vital resources provided by underground water systems.

## Timeline

### 2026-09-13: International Cave and Karst Day marks first global observance

The first International Cave and Karst Day is being observed globally to highlight the importance of karst ecosystems, which provide drinking water for over a billion people and house unique biodiversity.

8 sources. https://clstr.news/cluster/international-day-of-caves-and-karst-established-by-unesco

### 2026-09-08: UNESCO celebrates first International Day of Caves and Karst in Italy

UNESCO's first International Day of Caves and Karst is being observed in Italy with scientific conferences in Sicily and educational cave visits in Palermo to promote geological heritage.

3 sources. https://clstr.news/cluster/unesco-celebrates-first-international-day-of-caves-and-karst-in-italy

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Cite as: UNESCO International Day of Caves and Karst establishment. CLSTR, https://clstr.news/situations/unesco-international-day-of-caves-and-karst-establishment