 In the late 15th century , the Zytglogge and the other Bernese gate towers were extended and decorated after the Burgundian Romantic fashion . The Zytglogge received a new lantern ( including the metal <unk> visible today ) , four decorative corner towerlets , heraldic decorations and probably its stair tower . The astronomical clock was extended to its current state . In 1527 – 30 , the clockwork was completely rebuilt by Kaspar Brunner , and the gateway was <unk> to provide a secure foundation for the heavy machinery . 
