Boris and Gleb
The oldest extant structure in Grodno is the Kalozha Church of Sts. Boris and Gleb (Belarusian: "Каложская царква"). 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.