Sofia is the 13th largest city in the European Union. It is surrounded by mountains, such as Vitosha by the southern side, Lyulin by the western side, and the Balkan Mountains by the north, which makes it the third highest European capital after Andorra la Vella and Madrid. Being Bulgaria's primate city, Sofia is home of many of the major local universities, cultural institutions and commercial companies. The city has been described as the triangle of religious tolerance. This is due to the fact that three temples of the three world major religions—Christianity, Islam and Judaism—are situated within one square: Sveta Nedelya Church, Banya Bashi Mosque and Sofia Synagogue. This triangle was recently expanded to a square and includes the Catholic Cathedral of St Joseph, Sofia.