The Cylindrical Bastion (Latrán No. 28) was gradually erected in the period around 1500 as part of the town fortifications. After the removal of the fortifications, the inside of the bastion was adapted to serve for residential purposes. Outside, however, it was preserved almost intact along with its medieval plaster, key-shaped loopholes and wooden framed roof space with loopholes.
An interesting detail are small apertures distributed in regular distances in the masonry. During the construction of the bastion stakes were put into the masonry, and the platform scaffolding was put onto these stakes. When the wall was finished the masons took down the scaffolding gradually while cutting off the supporting stakes, the ends of which often remained in the masonry. These days it is possible to determine the age of the wood by means of dendrochronology, and thus determine the time when the construction came into being.
Since the Middle Ages, Český Krumlov had extensive fortifications, which were removed almost entirely within the course of the 16th - 19th centuries. Of the original nine town gates only one has remained - Budějovická Gate, and apart from the Cylindrical Bastion a continuous stretch of the town wall has only been preserved in Kájovská Street.
Cylindrical Bastion is currently used as a hotel Krumlov Tower.