The Roman theatre of Verona should not to be confused with the Roman amphitheatre known as the Verona Arena. The theatre was built in the late 1st century BC. Before its construction, two walls were built alongside the Adige River, between the Ponte di Pietra and the Ponte Postumio, to protect it against floods.
Today only remains of the edifice are visible, recovered starting from around 1830. They include the cavea and the steps, several arcades of the loggias and remains of the stage. Part of the cavea was occupied by the church of S. Siro, built in the 10th century and restored in the 14th century. At the top of the hill there was an ancient temple, built on a series of terraces.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.