St. Stephen's Cathedral, the Stephansdom, has stood at Vienna's centre since 1137, and the city has been arguing over, building on and nearly destroying it ever since. The South Tower took 65 years to build, averaging about seven feet a year. The roof tiling dates to the 1800s.

Embedded in the tower's stone, you can still see Turkish cannonballs from the 1683 siege that nearly handed Vienna to the Ottoman Empire. The great Pummerin bell was cast from captured Turkish iron. Beethoven stood in the square outside and realised, hearing nothing when it rang, that he had gone deaf. Mozart was married here. So was Haydn, who began his career as a choirboy in this church.

VoiceMap's self-guided audio tours connect these threads at the cathedral door, tracing Mozart's wedding and Beethoven's silence to the German captain who, in 1945, defied orders to shell the building to rubble.