Every morning, someone winds the clock in Rostock's St. Mary's Church by hand. It has been ticking since 1472, still on its original clockwork.

The bottom dial is a calendar, currently covering 2018 to 2150 and updated every few centuries. Above it come the hours, the moon's phases and the month. At noon each day, the apostles file past Jesus for a blessing. The church nearly lost it in April 1942, when the sexton and his daughter reportedly put out the fires from three bombs.

VoiceMap's self-guided audio tour of Rostock's Old Town ends at the church door with the clock's story, then points you down to the harbour.