The town walls in Krupina were built between 1551 and 1564 from tuff mined in the Krupina town cadastre. Ottoman armies invaded Hungary and reached the territory of Slovakia and the town of Krupina in the first half of the 16th century. The fortifications were constantly improved under the supervision of imperial architects and withstood the artillery of Ottoman troops and other enemies thanks to an ingenious system of modern fortification elements, the bastions. The Turkish bastion is today used as the city's amphitheatre.