According to legend, Charlemagne discovered the graves of the city saints Felix and Regula at the current site of the Grossmünster and had a first church built as a collegiate church. The Grossmünster was founded in the 9th century and is considered an important historical landmark of the city. In the first half of the 16th century, the Grossmünster became the starting point of the German-Swiss Reformation under Huldrych Zwingli and Heinrich Bullinger. The theological school attached to the collegiate church at the time became the nucleus of the University of Zurich. The church is famous for its unique architecture with two towers that rise majestically above the skyline of Zurich. The church is an important tourist destination and offers a unique opportunity to explore the history and culture of the city. Visitors can admire the architectural beauty of the church and the impressive works of art and stained glass windows with which it is adorned. The church also houses a crypt that contains a number of historical objects, including a statue of Charlemagne.