Mouse Tower, a Gothic brick tower from the 14th century, is the most recognized monument in Kruszwica and the unofficial symbol of the town. It was built by the With the remains of walls, it is a part of defense castle remnants. The castle was founded by king Kazimierz the Great. In 1656, the castle was seized by the Swedish army which burnt it down as they were retreating.
In the late years of 18th century, the castle ruins were gradually dismantled and its bricks floated up the Noteć river to Inowrocław. During excavation works carried out in the early 20th century, a number of other fragments of the castle and movable objects of historic interest were discovered. In the northern part of the castle hill, relics of an early-mediaeval burg-city were found: wooden huts with clay threshing floors and hearths; clog-lined streets; numerous pieces of equipment; ornaments and implements (incl. e.g. glass beads, amber products, clay vessels, bronze and iron products).
The name of the tower derives from the folk legend. Prince Popiel ІІ (or Duke Popiel) was a legendary 9th century ruler of the West Slavic tribe of Goplans and Polans. According to the chroniclers Gallus Anonymus, Jan Długosz and Marcin Kromer, as a consequence of his bad rule he was deposed, besieged by his subjects, and eaten alive by mice in a tower in Kruszwica. However, it cannot be the site of the events described in the legend as it was erected some 500 years thereafter.References:
Easter Aquhorthies stone circle, located near Inverurie, is one of the best-preserved examples of a recumbent stone circle, and one of the few that still have their full complement of stones. It consists of a ring of nine stones, eight of which are grey granite and one red jasper. Two more grey granite stones flank a recumbent of red granite flecked with crystals and lines of quartz. The circle is particularly notable for its builders' use of polychromy in the stones, with the reddish ones situated on the SSW side and the grey ones opposite.
The placename Aquhorthies derives from a Scottish Gaelic word meaning 'field of prayer', and may indicate a 'long continuity of sanctity' between the Stone or Bronze Age circle builders and their much later Gaelic successors millennia later. The circle's surroundings were landscaped in the late 19th century, and it sits within a small fenced and walled enclosure. A stone dyke, known as a roundel, was built around the circle some time between 1847 and 1866–7.