Church of St. Paraskevi, a small crossed dome church with three naves and four pillars, is one of Russia's oldest churches. It is currently a museum and on the UNESCO World Heritage list as a part of Historic Monuments of Novgorod and Surroundings.
The church was built in 1207 by Novgorod merchants and is named after Saint Paraskevi, who was the patron saint of the merchants. Previously, at least two different wooden Saint Paraskevi churches were standing at the same place, one constructed in 1156 and the second one in 1191.
The church was rebuilt several times. In particular, the dome was made in the 18th century. Between 1954 and the 2000s, the church was extensively restored, and the early walls were uncovered.
The walls are constructed of plinthite and limestone. The church does not close analogs with other contemporary Novgorod buildings, however, it is in many respects similar to the Saint Michael Church in Smolensk. It is presumed that the Saint Paraskevi Church was build by Smolensk masters. The decorative elements used in the design of the church were however taken over by Novgorod architects and became common in Novgorod ecclesiastical architecture of the 14th and the 15th centuries.References:
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.