Stephansdom, Austria's most important Gothic building, is a conical cloud-shaped South tower. The blue and yellow mosaic tiles embedded in the roofs on both sides are particularly striking. After four centuries of continuous renovation, renovation and expansion, Stephen's Cathedral, the world's peculiar hybrid building, still stands in the heart of Vienna and becomes the symbol of Vienna. Inside the cathedral is a royal tomb (Kaisergruft), which houses Frederick III of the Holy Roman Empire and the coffin of Prince Ogen, who led Austria to defeat the Turks. It also contains the internal organs of 72 Habsburg members.