Basel is the third largest city in Switzerland after Zurich and Geneva. It is also a famous religious and cultural city in Europe. As the representative of the main cultural buildings in Europe, Basel Cathedral is a representative building of the city. The cathedral is a Gothic building of red sandstone. It has been built since the 11th century. At the top of the cathedral, it can overlook the Heilin Mountains in Germany and France. Mount Vogel offers a panoramic view of Basel as a whole.