Pont Vell is the ancient bridge which crosses the Riu de Santa Eulària (Santa Eulària river), the only river on the Spanish island of Ibiza. The bridge stands next to the modern road bridge on the western approach to the town of Santa Eulària des Riu. Today the bridges is only used as a footbridge with all other traffic restricted to the adjacent modern bridge.
Pont Vell was an important strategic crossing and was once the only way into Santa Eulària from the west. Its origins are considered to be Roman. The Rome Empire had made Ibiza a Federatae Civitae. The island was never conquered by the Romans and during a gradual period of Romanization the island saw an economic golden age which lasted from approximately 25 BC and AD 75. It is thought that it was during this period the first bridge was built by the Romans to access the north east Canton of the island. The bridge that stands today is probably built on the foundations of the Roman bridge. It has been estimated that this bridge was probably built in the sixteenth or seventeenth century.
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.