Shortly after the Romans founded Cologne in 50 AD, they built a wall around the city. The wall was first expanded in the tenth century, and again in 1106, but due to the continuing growth of the city a new, 7 meters high wall was built in the twelfth and thirteenth centuries.
The most important of the twelve gates that gave entrance to Cologne was the west gate, known as the Hahnentor. After their coronation in Aachen, German kings arrived in Cologne through this gate to revere the shrine of the Three Magi in the Cologne cathedral. The gate was built between 1235 and 1240 and was probably named after a citizen named Hageno, who owned the nearby land.
The Hahnentorburg has two semi-circular, crenellated towers. The city's coat of arms is depicted above the entrance. The tower was restored in 1890 by the city architect Josef Stubben; a memorial plaque commemorates the architect's construction of Neustadt (new city) between 1881 and 1898 outside the former city walls. The tower was severely damaged during the Second World War, but was later reconstructed.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.