In the time before mechanical watches and clocks, the sundial helped track the passing hours. Most of us think of sundials set on the ground, but in medieval Europe this type, mounted on a church or other building, was carefully laid out to reflect the correct time by the shadow of the needle.
More or less. How "more or less" is reflected in the story of this one, a copy of one that stood in Berlin's Krogel area from the 14th century to the mid-1930s. It bore an inscription in Latin that translates properly to "Death is certain, but the hour is not." The locals rendered this as "It's dead certain that the clock is imprecise."
This copy is in Berlin's Nikolaiviertel, a 1970s reconstruction of one of the city's oldest quarters, destroyed in World War II. The area centers around the Nikolaikirche, with its distinctive twin spires.