The Monastery of Serra do Pilar has been a Cultural Heritage of Humanity site since 1996 and provides an unequalled view of the city of Porto. Its construction began in 1538 and it was completed in 1670. It housed the Augustinian Friars of the Monastery of Grijo until it became occupied by the Liberal army during the Civil War of 1832-1834, during which it was damaged. The Royal Brotherhood of Nossa Senhora do Pilar, established in 1834 and, later, the Group of Friends of the Monastery of Serra do Pilar, created in 1925, helped save the monastery.
The church with its circular floor plan is unique in Portugal, as is the Cloister, which is also circular and is lined with 36 Ionic columns. It currently houses North Heritage. In the cloister, note the statue of D. Afonso Henriques, by Soares dos Reis, which is the plaster version of the one in bronze at the Guimarães Castle. It is worth taking the guided tour which includes a climb to the dome. It's a 100 steps to the circular terrace that surrounds the dome of the church, but the panoramic view over Porto is spectacular.
Serro de Pilar is part of the UNESCO World Heritage site Historic Centre of Oporto, Luiz I Bridge and Monastery of Serra do Pilar.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.