Relicts of the city moat were uncovered on Św. Trójcy Street and St. Nicolas Square. The moat ran slantways through the square and down Schodowa Street. The moat was a crucial element of the city fortification. The moat was probably dug in Bielsko origins (the end of the 13th century). It was a dry moat in shape of a trough (width 10-11m) it ran outside the medieval city wall, which previously had been an embankment.