Read this: Traditional sports include Swiss wrestling or "Schwingen". It is an old tradition from the rural central cantons and considered the national sport by some. Hornussen is another indigenous Swiss sport, which is like a cross between baseball and golf. Steinstossen is the Swiss variant of stone put, a competition in throwing a heavy stone. Practiced only among the alpine population since prehistoric times, it is recorded to have taken place in Basel in the 13th century. It is also central to the Unspunnenfest, first held in 1805, with its symbol the 83.5 kg stone named Unspunnenstein.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What is thrown in the Swiss competition Steinstossen?
a heavy stone