abstract:International Union of Speleology ( UIS) is a non-profit, non-governmental organization formed in 1965 on the initiative of the International Speleological Congress (held every four years since 1949) to promote interaction between academic and technical speleologists from a wide range of nationalities for the purpose of developing and coordinating international speleology in all of its scientific, technical, cultural and economic aspects. Its voting members consist of a delegate from each member country representing the cavers and speleologists of that country, rather than any of the official national bodies.