Ulm Minster (German: Ulmer Münster) is a Lutheran church located in Ulm, Germany. Until the eventual completion of Sagrada Familia in Barcelona, Spain, it will remain the tallest church in the world, and the 5th tallest structure built before the 20th century, with a steeple measuring 161.5 metres (530 ft). Although sometimes referred to as Ulm Cathedral because of its great size, the church is not a cathedral as it has never been the seat of a bishop. Though the towers and all decorative elements are of stone masonry, attracting the attention of visitors, most of the walls, including the façades of the nave and choir, actually consist of visible brick. Therefore, the building is sometimes referred to as a brick church. As such, it lays claim to the rank of second- to fourth-largest, after San Petronio Basilica in Bologna and together with Frauenkirche in Munich and St. Mary's Church in Gdansk. Ulm Minster was begun in the Gothic era but not completed until the late 19th century. Nevertheless, all of the church except the towers and some outer decorations was complete, unlike Cologne Cathedral, where less than half of the work had been done, when it ceased. 768 steps lead to the top of the minster's spire. At 143 m (469 ft) there is a panoramic view of Ulm in Baden-Württemberg and Neu-Ulm in Bavaria and, in clear weather, a vista of the Alps from Säntis to the Zugspitze. The final stairwell to the top (known as the third Gallery) is a tall, spiraling staircase that has barely enough room for one person.