NSS Convention 2026

The International Union of Speleology (UIS) promotes the advancement of science, protection, and management of the world's speleological and karst heritage. UIS does not have individual members but 57 member countries, each represented by the country's national speleological organization. The USA is represented by the National Speleological Society (NSS). UIS has 20 commissions advancing specific aspects of speleology. Every four years, one member country hosts an International Congress of Speleology, the world's most significant speleological conference. At the Congress, member country delegates meet as the General Assembly to elect a new Bureau and make decisions to guide the UIS for the next four years.

In 2021-2022, the UIS organized the International Year of Caves and Karst to educate the world about the vital significance of speleological concerns. UIS was joined by 263 partner organizations from 51 countries to organize at least 1,491 events worldwide. The documented events reached at least 321 million people. The International Year was supported by UNESCO, the United Nations (UN) Educational, Scientific and Cultural Organization, but was not an official UNESCO or UN program. To build on that success, UIS proposed an International Day of Caves and Karst to UNESCO through Slovenia. Because over 60 member countries stepped up to co-sponsor with Slovenia, UNESCO approved recognition of the International Day of Caves and Karst in November 2025. The International Day of Caves and Karst (IDCK), observed annually on September 13th, will promote the importance of caves and karst with UNESCO's official support. Start planning your events now! Designate existing events in the September timeframe as IDCK events. Involve your local governments, businesses, schools, and media! We encourage all NSS Grottos, Regions, and Internal Organizations to seize this fine opportunity for cave and karst public outreach education.