Kost Castle is is privately owned by Kinský dal Borgo noble family. It was first proposed by Beneš von Wartenberg in 1349 as a possible construction site and was completed by his son Peter von Wartenberg. It retains most of the original features and is overall very well preserved and maintained.
The castle is known for its so-called 'White tower'. In about 1414 the family of Zajíc von Hasenburg moved there; later the family of Schellenberg (1497 - 1524), Lobkowicz (till 1576) and others; in this time some more buildings were built near the castle and joined to it.
Unlike most other castles in Bohemia, it does not lie on a hill, but on a spit between two brooks. Another peculiarity is the tower, which has a trapezoid-like ground-plan. The trapezoidal tower has the corners facing the areas of most likely catapult attacks. This is to make the missiles glance off the tower walls instead of hitting it headon thereby minimizing the damage.
The castle is open to the public and hosts events and exhibitions.References:
The Kalozha church of Saints Boris and Gleb is the oldest extant structure in Hrodna. It is the only surviving monument of ancient Black Ruthenian architecture, distinguished from other Orthodox churches by prolific use of polychrome faceted stones of blue, green or red tint which could be arranged to form crosses or other figures on the wall.
The church is a cross-domed building supported by six circular pillars. The outside is articulated with projecting pilasters, which have rounded corners, as does the building itself. The ante-nave contains the choir loft, accessed by a narrow gradatory in the western wall. Two other stairs were discovered in the walls of the side apses; their purpose is not clear. The floor is lined with ceramic tiles forming decorative patterns. The interior was lined with innumerable built-in pitchers, which usually serve in Eastern Orthodox churches as resonators but in this case were scored to produce decorative effects. For this reason, the central nave has never been painted.
The church was built before 1183 and survived intact, depicted in the 1840s by Michał Kulesza, until 1853, when the south wall collapsed, due to its perilous location on the high bank of the Neman. During restoration works, some fragments of 12th-century frescoes were discovered in the apses. Remains of four other churches in the same style, decorated with pitchers and coloured stones instead of frescoes, were discovered in Hrodna and Vaŭkavysk. They all date back to the turn of the 13th century, as do remains of the first stone palace in the Old Hrodna Castle.
In 2004, the church was included in the Tentative List of UNESCO"s World Heritage Sites.