Undoubtedly, it is one of the most beautiful monuments on the Trail of Eagles' Nests. A monumental castle building lies on a hill. For some its shape resembles a boat. In spite of many years of being in ruins it is still fairly impressive. The Mirowska fortress is one of the oldest fortifications of the Kraków-Częstochowa Upland. We know that a stone watchtower was erected in the mid-fourteenth century, during the reign of Casimir the Great.