St. John Apostle and Evangelist (Iglesia de San Juan Apóstol y Evangelista) is a Roman Catholic Asturian pre-Romanesque church situated in Santianes de Pravia. The church contains a foundation stone in the form of a letter labyrinth ('Silo Princeps Fecit') that records the 8th-century founding of the church by King Silo of Asturias. The inscription Silo princeps fecit singularly combined in fifteen horizontal lines and nineteen perpendicular columns of letters. The T forms the beginning and the end of the first and last line in consequence of which the name Silo is not to be found till the eighth line and the S which begins it is exactly in the centre of that line and of the tenth column thus the name is in the shape of a cross as the letters above below and on each side of the S form the word Silo.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.