Kremnica received stone fortifications, independent of the town castle, at the beginning of the fifteenth century on the initiative of king Sigismund I. In the sixteenth century, the defensive walls were modernized, by adapting them to the use of firearms. The town has never been captured. Two town gates and part of the walls were demolished in the 1880s.
The defensive wall in Kremnica surrounded the former historical center of the royal mining town with an area of approximately 45000 m2. Its height ranged from 5 to 7 meters. In the southern corners, it was reinforced with two cylindrical towers: the Red Tower in the southeast and the Black Tower in the southern corner. Similar towers were also located on the northern corners. Three gates led to the town: from the north the Upper Gate, from the south the Lower Gate towards Šášov and from the east Bystrzyca Gate, also called the Small.
In the sixteenth century, the towers and walls received arrowslits adapted to firearms, and in 1560 before the Lower Gate, a barbican was built, protected from the front by a massive tower. To increase the defense from the southern side, a ditch connecting two streams was dug.
Currently the best preserved is the Lower Gate complex with the barbican and the southern section of the walls with the Black and Red towers. In addition, a large part of the eastern section and the northern part have been preserved. The walls integrated into the building are also visible from the west. There is a tourist information center in the barbican tower.