This cover from Switzerland depicts a minisheet issued in 2023 celebrating the
Swiss Tectonic Arena Sardona, inscribed as a natural UNESCO site since 2008. The Glarus Alps feature a major thrust fault, a geological phenomenon where older rocks are carried onto younger layers in the process of mountain building. As this area is well accessible, it has played an important role in the studies of tectonic processes and geological sciences since the 18th century.
