As everyone knows, towns in the past were different. Leuven, which is located in Belgium, 20 km east of Brussels, is the capital of the so-called province of Flemish Brabant.
In the Middle Ages, it was protected by a huge wall, which was built during the 12th century. Its circumference was about 3/4 miles, and there were 11 town gates and 31 towers which had to keep off enemy. The construction structure is made of sand-lime stone and ironstone.
A few centuries later, the area was found out to be too cramped, so that another similar wall was built on the site where the Leuven ring road is located at present. The remains are just a few, but you can still see them nowadays.