The Chapel is a two-story building with a nearly square plan (7×7 m), which acquired its Late Classicist style in 1829. Its two-tiered facade with a triangular pediment, adorned with the Eye of Providence (a symbol of Divine protection), resembles a triumphal arch.
Inscribed on the pediment in Latin is Mater Misericordiae (Mother of Mercy), and below it—Sub tuum praesidium confugimus (“We fly to thy patronage”). Originally, the inscription was in Polish; however, following the defeat of the 1863 Uprising, it was replaced with the Latin one under pressure from the Tsarist administration. In 1933, the Polish version was restored, but today we see the Latin returned—the language of the universal Church, intended for all of the faithful.