Despite the many redecorations and renovations it has undergone in its 800 years of existence, the Zytglogge is one of Bern's most recognisable symbols and the oldest monument of the city,[1] and with its 15th-century astronomical clock, a major tourist attraction.

When the rapid growth of the city and the further expansion of the fortifications (up to the Käfigturm) relegated the tower to second-line status at around 1270–1275, it was heightened by 7 metres (23 ft) to overlook the surrounding houses.

In 1527–30, the clockwork was completely rebuilt by Kaspar Brunner, and the gateway was overarched to provide a secure foundation for the heavy machinery.

[9] The Zytglogge's exterior was repainted by Gotthard Ringgli and Kaspar Haldenstein in 1607–1610, who introduced the large clock faces that now dominate the east and west façades of the tower.

[8] In 1770–1771, the Zytglogge was renovated by Niklaus Hebler and Ludwig Emanuel Zehnder, who refurbished the structure in order to suit the tastes of the late Baroque, giving the tower its contemporary outline.

The shaft's seemingly massive corner blocks are decorative fixtures held in place by visible iron hooks.

[18] From atop the spire, the wooden pinnacle, copper-sheathed since 1930, rises an additional 15 metres (49 ft) into the skies, crowned with a gilded knob and a weather vane displaying a cut-out coat of arms of Bern.

[20] The inscription on the bell reads, in Latin: "In the October month of the year 1405 I was cast by Master John called Reber of Aarau.

The larger-than-life figure of bearded Chronos, the Greek personification of time, is traditionally nicknamed Hans von Thann by the Bernese.

[21] The wooden bell-striker, which has been replaced several times, has been a fixture of the Zytglogge since the renewal of the astronomical clock in 1530, whose clockwork also controls the figure's motions.

[24] The western clock face has similar hands, but is an integral part of Victor Surbek's 1929 fresco "Beginning of Time".

The painting depicts Chronos swooping down with cape fluttering, and, below the clockface, Adam and Eve's eviction from Paradise by an angel.

The principal hand of the clock indicates the time of day on the outer ring of 24 golden Roman numerals, which run twice from I to XII.

[27] The painted frieze above the astronomical clock shows five deities from classical antiquity, each representing both a day of the week and a planet in their order according to Ptolemaic cosmology.

From left to right, they are: Saturn with sickle and club for Saturday, Jupiter with thunderbolts for Thursday, Mars with sword and shield for Tuesday, Venus with Cupid for Friday and Mercury with staff and bag for Wednesday.

[31] The rooms above the clockwork mechanism were used by the city administration for various purposes up until the late 20th century, including as archives, storerooms, as a firehose magazine and even as an air raid shelter.

[32] The interior was frequently remodelled in a careless, even vandalistic fashion; for instance, all but three of the original wooden beams supporting the intermediate floors were destroyed.