Zamkavaja tower in Niasviž, Gothic bell tower in Niasviž, Belarus

The Zamkavaja tower is a 16th-century brick defensive tower on Mickiewicza Street in Niasviž, next to the Corpus Christi Church. It is a square, four-tiered structure with a hipped roof. The lower tier is a massive windowless base with buttresses; the second tier has rectangular, round and square openings alternating with blind niches; the third and fourth tiers each have three arched openings per face. White plastered surrounds contrast with the red brickwork.

The tower was built in the 16th century during the time when the Radzivil family used the castle as their residence and strengthened its defenses. It formed part of a broader defensive network that protected the entire castle complex from outside threats.

The tower now serves as the bell tower of the Corpus Christi Church, standing on the northern side of the church fence. Its name comes from the Castle Gate it once flanked in Niasviž's defensive walls, linking the castle with the town. It is listed in Belarus's State Register of Historical and Cultural Values.

The tower stands on the northern side of the church fence of the Corpus Christi Church on Mickiewicz Street, next to the former Jesuit monastery complex. It is a four-tier structure with a steep hipped roof, and the lower tier is a massive plinth with buttresses. Visitors should look for the white plastered frames around the openings, which contrast with the red brickwork.

The tower's design echoes the bell tower of the Trinity Church in Charnavchycy, built at the same time; both villages belonged to the Radziwiłł family. White plastered frames around the openings and bands between the tiers contrast with the red brickwork, giving the façades a two-colour scheme.