From a distance, the dome of the Zug clock tower appears blue-white but as you get closer to it, you can see the time on it. But not just the time, it also shows the month, the phase of the moon, the day of the week and whether it is a leap year or not. The tower was actually built as a way through the oldest city walls and later part of it was used as a prison as well as housing a room to keep warm by an open fire. Today the 52-metre-high tower is open to everyone, an opportunity not to be missed. After all, where else other than Zug can you get the key yourself to a city landmark.
The tower was originally built in the 13th century and heightened in 1478-1480. The current appearance dates from 1557.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.