Task: Question Generation
Input (English): Carnaval de Solsona takes place in Solsona, Lleida. It is one of the longest; free events in the streets, and nightly concerts run for more than a week. The Carnival is known for a legend that explains how a donkey was hung at the tower bell − because the animal wanted to eat grass that grew on the top of the tower. To celebrate this legend, locals hang a stuffed donkey at the tower that "pisses" above the excited crowd using a water pump. This event is the most important and takes place on Saturday night. For this reason, the inhabitants are called "matarrucs" ("donkey killers").
Output (English): What is one of the longest free events in the streets?