Located on a conglomerate promontory, between the steep canyons of the rivers Sava and Kokra, the town was naturally well protected and thus appealing for settlement from as far back as the stone age (4th millennium B.C.), but because of its strategic position by the entrance to the Gornjesavska valley it had to be protected during various historical periods with defence walls and towers. The city was most vulnerable in the north where the remains of a prehistoric defence moat from the 7th century B.C. are archaeologically confirmed, while the medieval defence walls were ten meters wide (along today’s Reginčeva street). The entire length of the town’s defence walls was 870 meters and additionally fortified with nine towers; one is partially preserved on Škrlovec and has distinct architectural elements of the 15th and the early 16th centuries. These are characteristic of the defence works of Prince Frederick III at the end of the Turkish invasions into the Zgornje Posavje region (1471, 1473, 1475, 1478, 1480, 1483 and 1491). The defence tower on Škrlovec also served to store armoury.