The Zytglogge, an ornate astronomical calendar clock, was once part of the western gate of Bern during the late 12th and early 13th centuries. The tower has had three clocks over its lifetime -- the first clocked was burned in a fire, the second one quit working and the third one, in use today, was built by Caspar Brunner in 1530. The twirling mechanisms begin four minutes before each hour and include a rooster, a bear and Chronos, the Greek god of time with an hourglass.