What is "steinstossen"

Steinstossen is the Swiss variant of stone put, a competition in throwing a heavy stone. Practiced among the alpine population since prehistoric times, it is recorded to have taken place in Basel in the 13th century. During the 15th century, it is frequently recorded to have been practiced alongside the Schützenfeste of the Old Swiss Confederacy. It is also central to the Unspunnenfest, first held in 1805, with its symbol the 83.5 kg Unspunnenstein.

Stones used at festivals in Switzerland are of varying sizes and weights, but usually are not much over 50 kg.