The United Nations Educational, Scientific and Cultural Organization (UNESCO) has added a third Polish geological site to its World Heritage List. It is the Tarnowskie Góry Lead-Silver-Zinc Mine and its Underground Water Management System (go.nature.com/2xez7jy; see also go.nature.com/2ytbhny and go.nature.com/2hyzhii).

Metallic ores have been extracted from the site since the twelfth century. A galena lead ore deposit discovered there in 1526 was mined until it ran out in 1912. The mine was abandoned in the 1930s, and a museum and underground tourist route were eventually opened there in 1976 (V. Coppola et al. Miner. Deposita 44, 559–580; 2009).

The vast labyrinths under Tarnowskie Góry also house a water station and more than 150 kilometres of drainage galleries. This ingenious gravity-based water-management system conserved the excess water from the mine for public use. It still operates today, largely in the way it was designed more than two centuries ago. The mine now forms one of Poland's largest overwintering areas for bats.

To be included on the World Heritage List, sites must be of exceptional universal value. The Tarnowskie Góry site qualifies because it is “a masterpiece of human creative genius” and “an outstanding example of a technological ensemble that contributed to significant stages in human history”.